Optical information recording medium, optical information recording apparatus and method

ABSTRACT

The present invention is applicable to a recording apparatus of a CD or DVD, a recording method thereof and a recording medium, and an object of the present invention is to clearly record a second information such as characters and figures between two recording levels in an optical disk. The second information is recorded in a predetermined area in a radius direction and a angular direction on the optical information recording medium, and further, the second information is recorded according to a change of a pit width based on a change of power of the laser beam, a change of a pit length based on an on/off control of the laser beam, or a change of depression or bulge of the pit based on a change in the vicinity of the on/off control of the laser beam. Whereby it is possible to record the second information such as a watermark pattern or a visible image, which is capable of being confirmed by seeing a disk.

TECHNICAL FIELD

The present invention relates to an optical information recordingapparatus and method, and an optical information recording medium. Forexample, the present invention is applicable to a recording apparatusfor a compact disk (CD) and a digital video disk (DVD), and to itsrecording method. According to the present invention, a positionalinformation of laser beam irradiation position on a polar coordinate isconverted into a positional information on a rectangular coordinate soas to access the corresponding image data, and then, in accordance withthe image data, a laser beam power is controlled. Whereby it is possibleto readily and visibly record characters and images in an informationrecording surface of a CD or the like.

Moreover, according to the method determined based on the CD and DVDstandards, a recording laser is turned on and off, and thereby,information such as music and a video signal is recorded on an opticaldisk. Simultaneously, the recording laser output (power) is gentlyvaried, and thereby, it is possible to record a second information whichis not determined in the CD and DVD standards, in the identical opticaldisk.

In the present invention, according to the method determined based onthe CD and DVD standards, a recording laser is turned on and off, andthereby, information such as music and a video signal is recorded on anoptical disk. Simultaneously, a luminous pulse of the recording laser isdivided into two parts, or is made so as to have a depressed portion,and thereby, it is possible to record a second information which is notdetermined in the CD and DVD standards, in the identical optical disk.

Further, the optical information recording medium of the presentinvention can record a new information such as a watermark capable ofbeing visibly confirmed by seeing a disk, a visible image or the like,in addition to the above information such as music and a video signaldetermined based on the CD and DVD standards.

BACKGROUND ART

Conventionally, in this type of optical information recording medium,for example, a compact disk, a data used for recording is subjected todata processing, and thereafter, is modulated according to an EFM (Eightto Fourteen Modulation)(hereinafter, referred simply to as“EFM-modulated”). In this manner, a pit line is formed in the compactdisk, and has a period 3T to 11T with respect to a predetermined basicperiod T, and thereby, an audio data or the like is recorded.

On the contrary, in a compact disk player, a laser beam is irradiated toa compact disk, and then, a return light is received, and thereby, it ispossible to obtain a regenerative signal of the return light, which hasa signal level which varies in accordance with a light quantity. Then,the regenerative signal is binarized according to a predetermined slicelevel so that a binary signal is generated. Further, according to thebinary signal, a PLL circuit is driven so as to generate a reproducingclock, and the binary signal is successively latched by the reproducingclock, and thereby, it is possible to generate a reproductive datahaving a period 3T to 11T corresponding to a pit line formed in thecompact disk.

The compact disk player decodes the reproductive data thus generatedaccording to the data processing corresponding to data processing inrecording, and then, a pit line is formed on a compact disk substrate.Further, a reflection film is formed on the disk substrate, and thus, aninformation recording surface is formed thereon. Moreover, characterssuch as a title, a name of music and a maker name, and images arevisibly printed on the information recording surface according to screenprocess printing.

DISCLOSURE OF THE INVENTION

For example, according to Japanese Patent Application No. 8-205292 asfiled on Jul. 16, 1996 by the applicant, the following optical diskapparatus has been disclosed therein. More specifically, in accordancewith all signal pattern to be recorded, a displacement shifted from anideal edge position of the regenerative signal is determined, and then,a table is prepared. Further, with the use of the table, an edgeposition of a recording signal is varied and recorded in accordance witha recording signal pattern, and thereby, a jitter can be removed. Thus,it is possible to overlap and record characters and figures, that is, asecond information which is not included in the CD standards, in asignal recording area of the compact disk (CD). Further, according toJapanese Patent Application No. 9-67843 as filed on Mar. 5, 1997 by theapplicant, the following optical disk apparatus has been disclosedtherein. More specifically, an ID pattern such as a bar code by awatermark is recorded in a read-in or signal recording area of anoptical disk, and then, the pattern is electrically detected. By doingso, a disk ID or cipher is read out so as to prevent a copy or piratededition of the optical disk from appearing on the market. Further,according to Japanese Patent Application No. 9-298328 as filed on Oct.30, 1997 by the applicant, the following optical disk apparatus has beendisclosed therein. More specifically, in order to show a cuttingposition, the optical disk apparatus includes a circuit which converts apolar coordinate of a radius (track number) and a rotational speed(number of FG pulse) into a rectangular coordinate at a real time, andthereby, a data expressed by the rectangular coordinate system is usedas it is, and then, it is possible to carry out cutting. Of course,these optical disk apparatuses record an EFM-modulated signal which isdetermined in the compact disk standards, in addition to informationsuch as characters, figures or the like. Therefore, it is possible toreproduce an optical compact disk by the conventional player, and inaddition, characters and figures are recorded in the signal area of thedisk, so that a disk having a high value added can be manufactured.

Moreover, Japanese Patent application No. 9-347532 filed by the presentapplicant have disclosed an optical information recording apparatus, anoptical information recording method and an optical informationrecording medium, which can record second information such as charactersand figures recorded on a disk as a difference of laser output power,and as a result, can record a clear second information. In addition,Japanese Patent application No. 9-173811 filed by the present applicanthave disclosed an optical disk recording apparatus, an optical disk andan optical disk reproducing apparatus (player), which divides a pithaving a period 9T or more into 4T+1T+4T so that a space is recorded asthe center 1T in place of a pit, and thereby, can record a newinformation depending upon the pit whether or not it is divided intotwo.

According to the invention disclosed in the aforesaid PatentApplications, there is the possibility that a signal characteristic isvariable in boundary portion where a laser output varies; for thisreason, a change of the laser output is not too widely taken. As aresult, there is a problem that the recorded second information such ascharacters and figures are not clear. Moreover, in production and saleof the optical disk such as CD and DVD, a illegal copy and an expansivesale of disk are an important matter. One method for preventing theillegal copy is to record a watermark (pattern) on the disk similarly tothat carried out in bills (paper money). The recorded watermark is avisible or dim image, or an invisible signature which is visibly stoodout on an information layer of the disk detected by a special hardware.The disk having the watermark is not transferred even in the case ofbeing copied by a conventional technique; therefore, it is possible tosimply confirm a truth of the disk.

Unexamined Patent Publication (Kokai) No. 10-31825 has disclosed amethod of recording a watermark (pattern) on an optical disk by varyinga size of an information pit. In two areas on the disk having aninformation pit of different size, a contrast of reflection light isvisible to a user (observer). In order to manufacture the disk asdescribed above, a laser beam intensity (power) in a mastering processis modulated in accordance with a pattern to be recorded.

When reading out the disk, a regenerative signal generated as the resultis affected by a size of the modulated pit. In order to reproduce thedisk with the use of the conventional reproducer (player), a pit edgeposition is corrected so as to shape the regenerative signal forcorrectly reproducing the disk by the reproducer. Further, in order tosecurely and safely reproduce the disk, a change from a certain powerlevel to other power level is carried out by slowly varying an opticalmodulation input voltage of a mastering machine, in place of suddenlychanging a voltage.

In order to achieve a desired smooth change, the modulation voltagechanging function must be carefully selected on the basis of thefollowing three problems.

First, an optical modulator for modulating a light intensity has anon-linear characteristic to be considered. secondary, a opticalintensity level of the optical modulator and a shift of an informationpit edge are interacted, and must be properly selected. Thirdly, thecharacteristic of the optical modulator depends upon an alignment of amastering machine, and is variable according thereto.

The following is a description on the most simple method for solving theabove problems. In the case of transferring the light intensity from acertain light intensity to other light intensity, a voltage of theoptical modulator is gradually variable at an equal voltage step.Simultaneously, in each modulation voltage, a pit edge position isgradually moved bit by bit according to an linearly interpolated value.According to this method, the optical modulator is operated well unlessit has non-linear characteristic. However, when a cutting operation iscarried out by using a simple interpolation, in the case of using anoptical modulator having a non-linear characteristic, in a regenerativesignal RF of the manufactured optical disk, an overshoot is generated inenvelop; as a result, a jitter is worsen.

The proper method for recording the conventional watermark pattern isrealized by collectively changing a light intensity level of a recordinglaser during disk mastering. However, according to this conventionalmethod, if the recording power is collectively changed during mastering,an non-alignment portion is generated in the vicinity of a change pointin a waveform of the regenerative signal, and there is a problem thatdepending upon a player, an error rate is worsen in the vicinity of thechange point.

Further, the above Unexamined Patent Publication (Kokai) No. 10-31825has disclosed a method of correcting a waveform (figure) of theregenerative signal by replacing a pit edge depending upon a recordingpower level. This shows that according to a change of signalcharacteristic, in a change of the watermark patter allowable in theplayer, a laser power is slowly changed. However, there is a problemthat the non-linearity of the optical modulator must be speciallyconsidered.

Unexamined Patent Publication (Kokai) No. 7-201079 has disclosed atechnique of forming a reflection layer on a surface of a card main bodyusing a phase-change area such as a phase-change layer as a visibly orinvisibly information such as characters, pictures and patterns.However, the above Unexamined Patent Publication (Kokai) No. 7-201079has no any consideration relative to the aforesaid problems.

It is, therefore, an object of the present invention to provide anoptical information recording medium, an optical information recordingapparatus and an optical information recording method, which can clearlyrecord a second information such as recorded characters and figures inan information recording surface of a compact disk.

In order to solve the above problems, according to the presentinvention, in the optical information recording apparatus and method, apositional information by a polar coordinate based on a rotation of theoptical information recording medium is converted into a positionalinformation by a rectangular coordinate, and then, the positionalinformation by the rectangular coordinate is addressed so as to outputan image data, and thus, in accordance with the image data, a laser beampower is varied.

The laser beam power is varied in accordance with the positionalinformation by the polar coordinate so as to vary a pit width, andthereby, it is possible to change a reflection factor of the informationrecording surface in synchronous with a rotation of the opticalinformation recording medium, and thus, to visibly record characters andimages. At this time, the positional information by the polar coordinateis converted into the positional information by the rectangularcoordinate so as to access the image data, and thereby, the rectangularcoordinate used in various information apparatuses is addressed, and forexample, a binary image data is used as it is, and thus, characters andfigures can be recorded. Therefore, it is possible to readily record avisible character and image.

Further, according to the present invention, it is possible to record asecond information such as characters and figures recorded on a diskwith the use of a difference of laser output power; as a result, a clearsecond information can be recorded. In addition, in the opticalinformation recording medium of the present invention, it is possible tomake large a change of the pit width by the second information, so thatthe second information can be more clearly confirmed.

Further, according to the present invention, a modulation signal, whichis variable in accordance with the first information, is generated, anda time changing signal, which is variable according to the secondinformation with a time, is generated. Then, a laser power is variedaccording to the time changing signal, and a laser beam obtained fromthe change of output power is on/off-controlled according to themodulation signal, and thereby, a change of the laser power by thesecond information is gently carried out. Moreover, the firstinformation is recorded by mainly varying a pit length and position; onthe other hand, the second information is recorded by mainly varying apit width. Whereby a change of the pit width by the second informationis stepwise carried out.

Further, according to the present invention, in accordance with thefirst information, a signal level is changed over at a period of integermultiples of a predetermined basic period, and thereby, a firstmodulation signal is generated, and then, a relative positionalinformation on a disk-like recording medium is detected by means of apickup. In accordance with the relative positional information, thesecond information is generated, and then, according to the secondinformation, a part of the modulation signal is modified, and thus, thelaser beam is modulated according to an output of the second modulationmeans.

The first information is recorded by mainly changing the pit length andposition, and the second information is recorded in a manner that of thepits, a pit having a predetermined length or more is divided into twoparts or if formed so as to have a depression or bulge, and thus, thesecond information forms a two-dimensional pattern on the opticalinformation recording medium.

Further, according to the present invention, when slicing into a binaryin reproducing, a time of the recording signal is previously correctedso that no jitter is generated.

Further, according to the present invention, a transition area of a pitchange based on the second information ranges from 0.1 mm to 1 mm;therefore, a pattern is not dim, and the second information can beclearly confirmed.

Further, according to the present invention, a laser intensity of themodulated laser beam is measured, and a driving signal of the modulatedlaser beam is controlled, and further, an intensity characteristic ofthe laser beam is measured with respect to a predetermined pair ofamplitudes of the driving signal. In this manner, an invert operation ofthe above characteristic is carried out so as to store an invertoperation value which is a driving signal corresponding to a certainpower intensity.

Then, a timing correction value relative to an intermediate powerintensity level is determined in a displacement period for linearlyinterpolating a timing value at a predetermined power intensity level,and thereby, in an invert operation for storing the invert operationcharacteristic for outputting a desired power intensity, the laser powerintensity is directly controlled during a change period forinvestigating a necessary driving amplitude. As a result, theregenerative signal of the optical information recording medium has asmooth change in a range where a recording power intensity varies, andthereby, the optical information recording medium can be stablyreproduced.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing a construction of an optical diskapparatus according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a rectangular coordinate positiondetecting circuit of this first embodiment.

FIG. 3 is a block diagram showing a construction of a coordinatetransforming circuit of this first embodiment.

FIG. 4 is a view showing a state of coordinate transformation in thecoordinate transforming circuit of this first embodiment: FIG. 4A is aview showing a positional information of a polar coordinate system, andFIG. 4B is a view showing a positional information of a rectangularcoordinate system.

FIG. 5 is a view to explain an operation of a character signalgenerating circuit of this first embodiment: FIG. 5A is a view showing apattern to be drawn on a disk, and FIG. 5B is a view showing a patternrecorded in an internal memory of the character signal generatingcircuit.

FIG. 6 is a block diagram showing a construction of an edge positioncorrecting circuit of this first embodiment.

FIG. 7 is a block diagram showing a construction of a rise edge positioncorrecting circuit of this first embodiment.

FIG. 8 is a signal waveform view showing a regenerative signal from apit by a 100% laser beam power of this first embodiment.

FIG. 9 is a signal waveform view showing a regenerative signal from apit by a 85% laser beam power of this first embodiment.

FIG. 10 is a signal waveform view showing a slice level change by adifference in the laser beam power in this first embodiment.

FIG. 11 is a signal waveform view showing a regenerative signal of acompact disk manufactured by the optical disk apparatus of the firstembodiment shown in FIG. 1.

FIG. 12 is a signal waveform view showing an operation of the edgeposition correcting circuit of this first embodiment.

FIG. 13 is a block diagram showing a construction of an optical diskapparatus according to a second embodiment of the present invention.

FIG. 14 is a block diagram to explain a construction of a staircasewaveform generating circuit of this second embodiment.

FIG. 15 is a timing chart to explain a count up operation and a countdown operation of the staircase waveform generating circuit of thissecond embodiment: FIG. 15A shows a second information SE, FIG. 15Bshows an up signal UP and a down signal DN, FIG. 15C shows a count valueSF, FIG. 15D shows an analog voltage signal SX, and FIG. 15E shows areference clock FK.

FIG. 16 is a view showing a transition area of a pit width of a secondinformation in this second embodiment.

FIG. 17 is a block diagram showing a construction of a voltage convertercircuit of this second embodiment.

FIG. 18 is a block diagram showing a construction of an optical diskapparatus according to a third embodiment of the present invention.

FIG. 19 is a block diagram showing a construction of a second modulatorcircuit of this third embodiment.

FIG. 20 is a block diagram showing a construction of a signaloverlapping circuit of the second modulator circuit of this thirdembodiment.

FIG. 21 is a view schematically showing an output signal from the secondmodulator circuit of this third embodiment, a pit obtained from theresult and a regenerative signal expected from the pit: FIG. 21A showsan output signal SD, FIG. 21B shows a recording pit, FIG. 21C shows aregenerative signal, FIG. 21D shows a two-division output signal SD, andFIG. 21E shows a regenerative signal.

FIG. 22 is a view showing a regenerative waveform in the case ofrecording the output signal of the second modulator circuit of thisthird embodiment on an optical disk.

FIG. 23 is a view schematically showing state of pit recorded on theoptical disk of this third embodiment: FIG. 23A shows an ordinaryrecording pit, FIG. 23B shows a two-division recording pit, and FIG. 23Cshows a depressed recording pit.

FIG. 24 is a block diagram showing a construction of an optical diskapparatus according to a fourth embodiment of the present invention.

FIG. 25 is a block diagram showing a construction of a power modulatorcircuit of this fourth embodiment.

FIG. 26 is a block diagram showing a construction of a CPU of thisfourth embodiment.

FIG. 27 is a view showing an output signal with respect to a change froma certain power level to other power level:

FIG. 27A shows a staircase signal SF and a control voltage signal ENVwith respect to a change of second information SE from a low level to ahigh level, and

FIG. 27B shows a staircase signal SF and a control voltage signal ENVwith respect to a change of second information SE from a high level to alow level.

FIG. 28 is a view showing a relationship between a driving voltage and ameasured laser beam intensity in this fourth embodiment.

FIG. 29 is a view showing a measurement example of a standardized laserbeam intensity of an optical acoustic modulator with respect to thedriving voltage in this fourth embodiment.

FIG. 30 is a view showing a regenerative signal in this fourthembodiment: FIG. 30A shows the case where the recording method of thepresent invention is not employed, and FIG. 30B shows the case where therecording method of the present invention is employed.

FIG. 31 is a view showing a process for preparing a correction valuetable of this fourth embodiment.

FIG. 32 is a flowchart showing a procedure of computer in this fourthembodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Description of First embodiment

FIG. 1 is a block diagram showing an optical disk apparatus according toa first embodiment. The optical disk apparatus 1 exposes a disk master 2so as to record an audio data SA outputted from a digital audio taperecorder 3 therein. At this time, a power of laser beam L used forexposure is varied according to a predetermined image data, and thus, apredetermined image and character are visibly recorded on an informationrecording surface of a compact disk. In a manufacturing process of anoptical disk, the disk master 2 is developed, and thereafter, issubjected to electro-forming, and thereby, a master disk is prepared,and then, a stamper is manufactured with the use of a mother disk.Further, in the manufacturing process of an optical disk, a disksubstrate is prepared by the stamper thus prepared, and then, areflection film and a protection film are formed on the disk substrate,and thus, a compact disk is manufactured.

More specifically, in the optical disk apparatus 1, a spindle motor 14rotatably drives the disk master 2, and an FG signal generating circuitheld on the bottom of the spindle motor 14 outputs an FG signal FG, inwhich a signal level rises every when the disk master motor is rotatedby a predetermined angle, to a spindle servo circuit 13 and arectangular coordinate position detecting circuit 5. In this firstembodiment, the FG signal FG outputs 4200 pulses every when the diskmaster 2 makes one rotation. The spindle servo circuit 13 drives thespindle motor 14 so that a frequency of the FG signal FG becomes apredetermined frequency, and thereby, the disk master 2 is rotatablydriven under the condition of a constant linear velocity.

A recording laser 9 comprises a gas laser or the like, and emits a laserbeam L for exposing the disk master. An optical modulator 10A comprisesan electrically acoustic optical element, and varies a power of laserbeam L in accordance with a second information SE so as to output thelaser beam L.

An optical modulator 10B comprises an electrically acoustic opticalelement, and makes an on-off control of the laser beam L according to amodulation signal S1 so as to emit the laser beam L. A mirror 11 bentsan optical path of the laser beam L so that the laser beam is emittedtoward the disk master 2, and then, an objective lens 12 converges areflection light by the mirror 11 onto the disk master 2. These mirror11 and objective lens 12 are successively moved to an outercircumferential direction of the disk master 2 by means of a threadmechanism (not shown) in synchronous with a rotation of the disk master2, and thereby, an irradiation position by laser beam L is successivelydisplaced toward the outer circumferential direction of the disk master2.

In the optical disk apparatus 1, a track is formed into a spiral shapedon the disk master 2 by moving the mirror and the objective lens 12 in astate of rotating the disk master 2, and then, a pit is successivelyformed on the track in accordance with a modulation signal S1. Further,at this moment, a pit width is varied in accordance with a secondinformation SE, and thereby, predetermined character and image arevisibly recorded.

FIG. 2 shows a construction of a rectangular coordinate positiondetecting circuit 5 used in the case of generating the secondinformation recorded in the above manner. In FIG. 2, a one-rotationcount circuit 20 and a track count circuit 21 are cleared by a clearpulse CLR from a system controller (not shown) at a start of recording,and then, the initial value becomes zero. The FG signal from the spindlemotor 14 outputs 4200 pulses every when the spindle motor 14 makes onerotation. When the one-rotation count circuit 20 counts 4200, the pulseis outputted as a count value RX. The count value RX takes values from 0to 4199, and is incremented by one count every when the spindle motor 14is rotated by 1/4200, and therefore, the count value expresses arotational angle of the spindle motor 14. Further, when the spindlemotor 14 makes one rotation, the counter is reset. Then, a pulse isgenerated as a signal RT every when the reset occurs, and the pulse thusgenerated is inputted to the track counter circuit 21.

The track count circuit 21 counts the signal RT of one pulse per onerotation of the spindle motor, and thereby, outputs a track number TKrecording at present. For example, in the case of recording a compactdisk (CD), recording is started at a position of the radius 23 mm of thecompact disk, and is carried out by the radius 58 mm thereof with atrack pitch of 1.6 micron. Thus, the value of the track count circuit 21changes 0 to about 22000 counts.

As described above, the count value RX of the one-rotation count circuit20 and the count value TK of the track count circuit 21 are equivalentto an angular information and a radius information in the case ofexpressing a position recording at present by a polar coordinate.Therefore, with the use of these two values, a coordinate transformingcircuit 22 calculates a positional information X and Y on a rectangularcoordinate system, and then, can output the positional information. Thepositional information X and Y on the rectangular coordinate system isconverted in the above manner, and thereafter, is transmitted to animage (character) signal generating circuit 6.

The coordinate transforming circuit 22 has a construction as shown inFIG. 3. As shown in FIG. 3, a CPU is connected with input ports 31 and32 while being connected with output ports 33 and 34. The count valuesRX and TK of the one-rotation count circuit 20 and the track countcircuit 21 are respectively connected to the input ports 31 and 32 sothat the CPU 30 can capture these count values.

The CPU 30 computes (calculates) positional information X and Y on arectangular coordinate system from these two count values according tothe following mathematical equations 1 and 2, and then, outputs them tooutput ports 33 and 34.X=A·(TK·Tp+Tb)·cos(2π·(RX/4200))+B  Mathematical equation 1:Y=A·(TK·Tp+Tb)·sin(2π·(RX/4200))+B  Mathematical equation 2:

In the mathematical equations 1 and 2, each of A and B is a constantdetermined by a dimension and position of coordinate system, Tb isindicative of a recording start radius, and Tp is indicative of a trackpitch. The transformation as described above is performed; as a result,a positional information expressed by a polar coordinate system (RX, TK)as shown in FIG. 4A is transformed into a rectangular coordinate system(X, Y) as shown in FIG. 4B.

The image (character) signal generating circuit 6 is composed of animage memory storing an image data, a ROM (Read Only Memory) storing acharacter data, etc. Further, the image (character) signal generatingcircuit 6 inputs an address of the output (X, Y) from the rectangularcoordinate position detecting circuit 5, and then, outputs a memoryoutput as a second information SE representing characters and figures.For example, in the case of drawing a pattern as shown in FIG. 5A on adisk, a pattern as shown in FIG. 5B is recorded in an internal memory ofthe image (character) signal generating circuit 6. Namely, this imagedata comprises a bit-map font binary data which constitutes charactersand figures to be recorded on a compact disk, and uses X and Ycoordinates as address. The image data is prepared with the use of acomputer, and is loaded in an image memory, and further, is set in theimage memory by an image reader using a scanner or the like.

Thus, in the optical disk apparatus 1, a power of laser beam L ischanged from a 100% laser power to a 85% laser power in accordance withthe second information SE, and then, a pit width is locally varied inaccordance with the image data. In the compact disk, a reflection factor(index) varies at a portion of a narrow-width pit and at a portion of anordinary pit width; therefore, characters and images by the image dataare visible.

As described above, in the case of varying the pit width and recording adigital audio signal SA, a modulator circuit 4 receives an audio data SAoutputted from the digital audio tape recorder 3, and then, adds thecorresponding sub-code data to the audio data SA. Further, the modulatorcircuit 4 processes the audio data SA and the sub-code data according toa compact disk format, and then, generates a modulation signal SB. Morespecifically, the modulator circuit 4 adds an error correcting code tothe audio data SA and the sub-code data, and thereafter, subjects thesedata to interleaving and EFM modulation processing. Therefore, themodulator circuit 4 outputs an EFM modulation signal SB having a signallevel which varies at a period (period 3T to 11T) of integer multiplesof a basic period T, to the basic period of pit format.

Edge position correcting circuits 7A and 7B detect a change pattern ofthe EFM modulation signal SB, and then, correct the timing of the EFMmodulation signal SB so as to reduce an interference between codes inaccordance with the change pattern, and thus, output modulation signalsS1A and S1B of the timing corrected result. At this time, the edgeposition correcting circuit 7A outputs an optical modulation signal S1Acorresponding to a 100% laser beam L outputted from an optical modulator10A; on the other hand, the edge position correcting circuit 7B outputsan optical modulation signal S1B corresponding to a 85% laser beam Loutputted from an optical modulator 10A.

In the manner as described above, a power of the laser beam L is changedfrom 100% to 85% so as to vary a pit width, and thereby, a signal levelof the regenerative signal varies. More specifically, in the cases of100% laser beam and 85% laser beam, as seen from an eye pattern of theregenerative signal RF shown in FIG. 8 and FIG. 9, amplitudes W1 and W2of the regenerative signal RF.

When observing the eye pattern as a continuous waveform, as shown inFIG. 10, slice levels SL1 and SL2 for properly binary-coding theregenerative signal are different between the case of 100% laser beamand the case of 85% laser beam. In other words, an asymmetry greatlyvaries between a portion of 100% laser beam and a portion of 85% laserbeam.

Then, if the regenerative signal RF is binarized (binary-coded)according to a constant slice level of the case of 100% laser beam, itis difficult to generate a binary-coded signal according to a propertiming (i.e., timing synchronous with a basic period T), and a greatjitter is generated in a reproductive clock. For this reason, it isdifficult to properly reproduce the audio data recorded in a compactdisk. Moreover, in the case where the regenerative signal by 85% laserbeam is sliced according to the slice level SL1 set in the case of 100%laser beam, for example, when the amplitude of the regenerative signalis small like a regenerative signal having a period 3T, the signal levelitself of the regenerative signal does not cross the slice level SL1. Asa result, not only a jitter is increased, but also a bit error isfrequently generated in a reproductive data reproduced by thebinary-coded signal.

In general, a compact disk player is provided with an automatic slicelevel adjusting circuit for correcting a slice level in accordance withthe aforesaid asymmetry. However, it is difficult to suitably cope witha sudden change of laser power; as a result, a very long burst error isgenerated in a portion just after the laser beam L power is changedover.

For this reason, in the optical disk apparatus 1, the edge positioncorrecting circuits 7A and 7B correct a pit length formed on the diskmaster 2, and then, individually output modulation signals S1A and S1Bfor correcting a timing of the EFM modulation signal SB so that in theregenerative signal RF by 100% and 85% laser beam, the regenerativesignal is binary-coded according to the identical slice level SL asshown in FIG. 11, and a binary-coded signal is generated according to acorrect timing.

Further, at this moment, the edge position correcting circuits 7A and 7Bindividually detect a change patter of EFM modulation signal SB, andthen, selectively output modulations signals S1A and S1B so as to reducean interference between codes from an adjacent code in accordance withthe change patter.

Namely, if the laser beam L power varies, a pit length varies; for thisreason, a degree of interference between codes also varies in each laserbeam power. Thus, the edge position correcting circuits 7A and 7Bcorrect the timing of EFM modulation signal SB so as to reduce a jitterof the regenerative signal RF generated by the interference betweencodes.

A data selector 8 selects and outputs the corresponding modulationsignals S1A and S1B in accordance with a change-over of the power oflaser beam L, on the basis of the second information SE outputted fromthe image (character) signal generating circuit 6.

FIG. 6 is a block diagram showing a construction of the edge positioncorrecting circuit 7A. Incidentally, the edge position correctingcircuit 7B has the same construction as the edge position correctingcircuit 7A except that a correction data stored in each of a rise edgecorrecting circuit 60A and a fall edge correcting circuit 60B isdifferent, and therefore, the overlapping description is omitted.

In the edge position correcting circuit 7A, a PLL circuit 61 generates achannel clock CK from the EFM modulation signal SB, and then, outputsit. In this case, in the modulation signal SB, a signal level changes ata period of integer multiples of a basic period T; for this reason, thePLL circuit 61 generates a channel clock CK having a signal levelchanging at a basic period T synchronous with the modulation signal SB,and then, supplies the channel clock CK to the rise edge correctingcircuit 60A and the fall edge correcting circuit 60B.

In the rise edge correcting circuit 60A, 13 latch circuits 70A to 70Moperated by the clock CK are connected in series, as shown in FIG. 7,and the EFM modulation signal SB is inputted to the series circuit. Therise edge correcting circuit 60A samples the EFM modulation signal SB atthe timing of channel clock CK, and thereafter, detects a change patterof the EFM modulation signal SB on the basis of the sampling results oncontinuous 13 points. More specifically, for example, in the case wherea latch output “0001111000001” is obtained, it is possible to make thefollowing decision; namely, the change pattern is a pattern in which apit of a period 4T continues after a space of a period 5T. Likewise, inthe case where a latch output “0011111000001” is obtained, it ispossible to make the following decision; namely, the change pattern is apattern in which a pit of a period 5T continues after a space of aperiod 5T.

A correction value table 71 comprises a memory storing a plurality ofcorrection data, and latch outputs of the latch circuits 70A to 70M areinputted thereto as lower 13 pits. Moreover, a staircase signal SF isinputted thereto as upper 3 bits of address in an embodiment describedlater. The staircase signal SF reflects a power of recording laser beamat present. Namely, the correction value table 71 can output acorrection value data corresponding to both the change pattern of themodulation signal SB and a change of the recording power. In this firstembodiment, the laser power (output) is not changed like a stair, andtherefore, the staircase signal SF is all set as 0.

A monostable multi-vibrator (MM) 72 receives a latch output from thecentral latch circuit 70G of the 13 latch circuits connected in series,and then, outputs a rise pulse signal having a signal level which risesup during a predetermined period (i.e., period shorter than a period3T), on the basis of a rise timing of the latch output.

A delay circuit 74 has a 15-step tap output, and a delay time differencebetween taps is set as a resolution power of timing correction of themodulation signal in the edge position correcting circuit 7A. The delaycircuit 74 successively delays a rise pulse signal outputted from themonostable multi-vibrator 72, and then, outputs it from each tap. Aselector 73 selectively outputs a tap output of the delay circuit 74according to the correction value data DF, and thereby, changes a delaytime in accordance with the correction value data DF, and thus,selectively outputs a rise pulse signal SS.

Namely, the rise edge correcting circuit 60A generates a rise edgesignal SS as shown in FIG. 12D. More specifically, in the rise edgesignal SS, a signal level rises in response to a rise of signal level ofthe EFM modulation signal SB, and each rise edge delay time Δr (3, 3),Δr (4, 3), Δr (3, 4), Δr (5, 3) . . . to the EFM modulation signal SB,changes in accordance with the change pattern of the EFM modulation SBand a recording laser power.

In FIG. 12, the change pattern of the modulation signal SB is expressedby a pit length p and a pit interval b with the use of one period aclock CK (i.e., channel clock) as a unit, and then, a delay time to arise edge is expressed as Δr (p, b). Therefore, in FIG. 12D, thesecondary described delay time Δr (4, 3) is a delay time in the casewhere there is a blank of 3 clock before a pit of 4 clock. Whereby thecorrection value table stores the correction value data DF correspondingto all of combinations of these p and b.

As described above, the rise edge correcting circuit 60A detects a pitpatter formed on an optical disk and a recording laser power over arange of period 12T using a basic period as a unit. Then, the rise edgecorrecting circuit 60A generates a rise edge signal SS in accordancewith the recording pattern and the recording laser power.

On the other hand, the fall edge correcting circuit 60B has the sameconstruction as the rise edge correcting circuit 60A except that themonostable multi-vibrator 72 is operated on the basis of a fall edge oflatch output, and the contents of the correction value table 71 differsfrom that of the rise edge correcting circuit 60A.

Thus, the fall edge correcting circuit 60B generates a fall edge signalSR as shown in FIG. 12C. More specifically, in the fall edge signal SR,a signal level falls in response to a fall of signal level of the EFMmodulation signal SB, and each rise edge delay time Δf (3, 3), Δf (4,3), Δf (3, 4), Δf (5, 3) . . . to the EFM modulation signal SB, changesin accordance with the change pattern of the EFM modulation SB and arecording laser power. Similar to the delay time with respect to therise edge, the change pattern of the EFM modulation SB is expressed by apit length p and a pit interval b, and a delay time with respect to thefall edge is expressed as Δf (p, b).

Namely, the fall edge correcting circuit 60B detects a pit patternformed on an optical disk and a recording laser power over a range ofperiod 12T using a basic period as a unit. Then, the rise edgecorrecting circuit 60B corrects a timing of the fall edge of themodulation signal SB at the timing after the laser beam irradiation inaccordance with the recording pattern and the recording laser power, andthus, generates a fall edge signal SR.

A flip-flop (F/F) 62 shown in FIG. 6 synthesizes the aforesaid rise edgesignal SS and fall edge signal SR, and thereafter, outputs it. Morespecifically, the flip-flop 62 inputs the rise edge signal SS and thefall edge signal SR to a set terminal S and a reset terminal R, andthereby, generates a modulation signal S1A (S1B) in which a signal levelrises at the rise of the signal level of the rise edge signal SS, andthereafter, a signal level falls at the fall of the signal level of thefall edge signal SR.

In the EFM modulation signal SB, a timing of the rise edge and the falledge is corrected in accordance with a length and interval of adjacentpits, or in accordance with an exposure position of a radius direction,and thereafter, is outputted. In response to the above timing, a timingof irradiating the laser beam L to the disk master 2 is corrected inaccordance with a length and interval of adjacent pits, or in accordancewith an exposure position of a radius direction.

Thus, in the optical disk apparatus 1, a front edge position and a rearedge position of each pit are corrected so as to reduce a jittergenerated by an interference between codes in reproducing. Moreover, thefront edge position and the rear edge position are corrected by means ofthe edge position correcting circuits 7A and 7B corresponding to eachpower of the laser beam L, and thereby, even in the case where the powerof laser beam L falls, the regenerative signal is binary-coded accordingto a constant slice level, and then, the front edge position and therear edge position of each pit are corrected so as to securely reproducethe audio data SA recorded by the pit length.

More specifically, in the case where the power of laser beam L is 100%,the front edge position and the rear edge position are corrected by themodulation signal S1A outputted from the edge position correctingcircuit 7A, and thereby, it is possible to properly generate abinary-coded signal according to the constant slice level. Moreover, inthe case where the power of laser beam L is 85%, the front edge positionand the rear edge position are corrected by the modulation signal S1Boutputted from the edge position correcting circuit 7B, and thereby, itis possible to properly generate a binary-coded signal according to thesame constant slice level as the case where the power of laser beam L is100%.

As described above, according to the first embodiment, the positionalinformation on laser beam irradiation position by the polar coordinateis converted into a positional information by the rectangular coordinateso that an image data is accessed, and then, in accordance with theimage data, the laser beam power is changed. Whereby it is possible toreadily and visibly record characters and images on an informationrecording surface of an optical information recording medium.

Description of Second Embodiment

A second embodiment of the present invention will be detailedlydescribed below with reference to the accompanying drawings.

FIG. 13 is a block diagram showing a construction of an optical diskapparatus according to a second embodiment of the present invention. InFIG. 13, like reference numerals are used to designate the partscorresponding to those shown in FIG. 1, and the details are omitted.

The second information outputted from the character signal generatingcircuit 6, obtained in the manner as described in FIG. 1, is inputted toa staircase waveform generating circuit 130. The staircase waveformgenerating circuit 130 detects a change of the second information, andthen, generates 3-bit staircase signal SF such that an output valuestepwise varies together with time. The staircase signal SF is convertedinto a signal SX having a stepwise voltage by means of a voltageconverter circuit 132, and then, is inputted to an optical modulator10A. Also, the staircase signal SF is inputted to an edge positioncorrecting circuit 131.

The optical modulator 10A changes an output power of laser beam L1according to the staircase signal SF whose voltage stepwise varies inaccordance with the second information SE such as characters andfigures. More specifically, in the case where the second information SEkeeps a level “1” for a long time, the optical modulator 10A passes thelaser beam L1 so that an output power of laser beam L2 becomes 100%.Conversely, in the case where the second information SE keeps a level“0” for a long time, the optical modulator 10A attenuates and passes thelaser beam L1 so that an output power of laser beam L2 becomes 85%. Inthe case where the second information transfers from the level “0” tothe level “1”, the power of laser beam L1 is stepwise changed from a 85%power to a 100% power. Likewise, the case where the second informationtransfers from the level “1” to the level “0”, the power of laser beamL1 is stepwise changed from a 100% power to a 85% power.

As described above, the optical modulator 10A outputs the laser beam L2whose output power is variable between 100% and 85% powers, according tothe output SF from the staircase waveform generating circuit 130.Sequentially, the laser beam thus obtained is turned on and off by meansof an optical modulator 10B. More specifically, in the case where thesignal SC outputted from the edge position correcting circuit 131 is alevel “1”, a laser beam L3 is turned on; conversely, in the case wherethe signal SC outputted from the edge position correcting circuit 131 isa level “0”, the laser beam L3 is turned off.

The mirror 11 bends an optical path of the laser beam 3 so that thelaser beam L3 is emitted toward the disk master 2, and then, theobjective lens 12 converges a reflection light by the mirror 11 onto thedisk master 2. These mirror 11 and objective lens 12 are successivelymoved to an outer circumferential direction of the disk master 2 bymeans of a thread mechanism (not shown) in synchronous with a rotationof the disk master 2, and thereby, an exposure position by the laserbeam L3 is successively displaced to the outer circumferential directionof the disk master 2.

Thus, in the optical disk apparatus 1, in a state that the disk master 2is rotatably driven, a spiral-like track is formed on the disk master 2by moving the mirror 11 and the objective lens 12, and then, a pit issuccessively formed on the track in response to the modulation signal SCand the second information SE such as characters and figures.

The modulator circuit 4 receives an audio data SA outputted from adigital audio tape recorder 3, and then, adds the corresponding sub-codedata to the audio data SA. Further, the modulator circuit 4 subjects theaudio data SA and the sub-code data to data processing according to acompact disk format, and then, generates a modulation signal SB. Morespecifically, the modulator circuit 4 adds an error correcting code tothe audio data SA and the sub-code data, and thereafter, subjects thesedata to interleaving and EMF-modulation processing. Whereby themodulator circuit 4 outputs an EFM-modulation signal SB having a signallevel which varies at a period (period 3T to 11T) of integer multiplesof a basic period T, with respect to the basic period T for pitformation.

In the optical disk apparatus conventionally used, the EFM-modulationsignal SB generated in the above manner is transmitted to an opticalmodulator 10B as it is, and then, a light beam obtained from a laser 9is turned on and off so that exposure is performed on the optical diskmaster 2.

In an optical disk manufactured according to the aforesaid conventionalmethod, a state of regenerative signal varies depending upon a recordingsignal pattern, and this is a factor of generating a jitter. To give anexample, in a disk recorded by using the conventional optical diskrecording apparatus, the following phenomenon has been observed; morespecifically, the minimum (smallest) size pit equivalent to a 3T signalis recorded in a state of always becoming smaller than an ideal size.For this reason, a signal from the pit corresponding the 3T signal isbinary-coded at a predetermined level, and thereafter, when observingthe signal, a pulse width becomes slightly shorter than that of the 3Tsignal, and this is a factor of generating a jitter.

Moreover, according to the conventional method, there is a problem thatwhen a power of recording laser varies, the optimum binary-coded levelvaries in the generative signal. For this reason, if the laser power ischanged between 100% and 85% outputs according to the second informationSE expressing characters and figures as this embodiment, there is aproblem that a player must change the binary-coded level according tothe laser power. In a reproducing apparatus (player), in the case wherea variation of the binary-coded level is not made well due to anycauses, an error is generated in the conventional method; for thisreason, it is impossible to carry out the aforesaid recording method.

In order to solve the above problem, according to this secondembodiment, the output signal SB of the modulator circuit 4 istransmitted to the edge position correcting circuit 131. The edgeposition correcting circuit 131 detects a change pattern of the EFMmodulation signal SB. Simultaneously, the staircase signal SF istransmitted to the edge position correcting circuit. Thus, the edgeposition correcting circuit 131 can correct an edge position accordingto information on both the change pattern of the EFM modulation signalSB and the recording laser power.

Then, in accordance with two kinds of information thus obtained, theedge position correcting circuit 131 outputs a modulation signal SCfinely adjusting an edge position. More specifically, in the edgeposition correcting circuit 131, a change timing of the output signal SCis finely adjusted in accordance with a recording laser power (valuefrom 85% to 100%) and the change pattern of EFM signal SB duringrecording (a pit length and a space length vary in a range from 3T to11T), and thus, the modulation signal SC is outputted so that a jitteralways becomes the best state. In this case, the edge positioncorrection 131 has the construction as shown in FIG. 6.

Namely, the modulation signal SC passing through the edge positioncorrecting circuit 131 is recorded by a predetermined laser powerexpressed by the staircase signal SF, and then, when reproducing a diskthus obtained, a signal including no jitter is obtained by binary-codinga regenerative signal according to a predetermined binary-coded levelVL.

BY the way, the staircase signal SF is a signal made from the secondinformation SE. The second information SE is constructed as a signalforming characters and figures in the case of visibly seeing a datarecorded on the disk. Therefore, in the disk recorded according to thissecond embodiment, a pit width varies according to the secondinformation SE; as a result, it is possible to see information such ascharacters and figures by visibly observing the disk surface.

Moreover, in this second embodiment, the laser power is slowly changed,and a proper correction is always carried out by means of the edgeposition correcting circuit 131 in response to the recording laserpower; therefore, in any reproducing apparatus (player), it is possibleto obtain a regenerative signal without causing a jitter. In addition, achange of the laser power is made large as compared with theconventional case; as a result, it is possible to record an informationsuch as characters and figures, which is capable of being visiblyobserved more clear than the conventional case, onto the disk surface.

In all recording laser power, a correction is always made by means ofthe edge position correcting circuit 131; therefore, this serves tosolve the following problem; more specifically, a pit formation isdelicately different for each pattern. As a result, it is possible tomanufacture a disk in which a jitter of the regenerative signal issynthetically lowered. Further, in this second embodiment, an edgeposition is adjusted for each recorded pattern; therefore, it ispossible to remove a jitter depending upon the pattern, that is, ajitter generated by an interference between codes.

An output level of the laser beam L2 is varied between 100% power and85% power by the output signal SC of the edge position correctingcircuit 131 thus obtained, and then, the laser beam L2 is on-offcontrolled by means of the optical modulator 10B, and thus, isirradiated as a laser beam L3 onto the optical disk master 2.

As described above, an image to be drawn is binary-coded with the use ofthe rectangular coordinate system, and then, is recorded in an internalROM of the character signal generating circuit 6. The informationrecorded in the ROM is inputted so that the coordinate system istransformed at a real time by means of the rectangular coordinateposition detecting circuit 5, and then, is read out as it is, and thus,is successively recorded on the disk as a change of the recording laserpower. However, in this case, when the output from the character signalgenerating circuit 6 transforms from a level 0 to a level 1, or from alevel 1 to a level 0, the staircase waveform generating circuit 130generates a staircase waveform SF so as to make gentle the outputchange.

FIG. 14 is a block diagram showing a construction of the staircasewaveform generating circuit 130. As shown in FIG. 14, the change fromthe level 0 to the level 1 of the second information SE is detected bymeans of the rise edge detecting circuit 140, and then, is supplied toan up/down counter 142 as a signal UP whose level is kept at a level 1for a predetermined time. The up/down counter 142 counts a referenceclock FK from a reference oscillator 143 for the duration when the upsignal UP is at a level 1 so as to count up an output value SF. On theother hand, the change from the level 1 to the level 0 of the secondinformation SE is detected by means of the fall edge detecting circuit141, and then, is supplied to an up/down counter 142 as a signal DNwhose level is kept at a level 1 for a predetermined time. The up/downcounter 142 counts a reference clock FK from a reference oscillator 143for the duration when the down up signal DN is at a level 1 so as tocount down an output value SF. The rise edge position detecting circuit140 and the fall edge position detecting circuit 141 for carrying outthe aforesaid operation may be composed of a monostable multi-vibrator,for example.

An operation of the staircase waveform generating circuit 130 having theaforesaid construction will be described below with reference to FIG.15. When a rise edge of the second information SE as shown in the firsthalf of FIG. 15A is generated, the rise edge detecting circuit 140outputs a pulse UP which becomes a level 1 for only time T as shown inFIG. 15B. In this case, the up/down counter 142 carries out a count-upoperation at a period of the reference clock FK as shown in FIG. 15E sothat a count value SF is successively increased from 0 to 7.Incidentally, although not shown, an up/down counter 142 is constructedso as to stop the count-up operation in order to prevent an overflowwhen the count value becomes 7.

On the other hand, when a fall edge of the second information SE asshown in the second half of FIG. 15A is generated, the fall edgedetecting circuit 141 outputs a pulse DN as shown in FIG. 15B. In thiscase, the up/down counter 142 carries out a count-down operation at aperiod of the reference clock FK as shown in FIG. 15E so that a countvalue SF is successively decreased from 7 to 0 as shown in FIG. 15C.Incidentally, although not shown, an up/down counter 142 is constructedso as to stop the count-down operation in order to prevent an underflowwhen the count value becomes 0.

FIG. 16 is a view showing a transition area of pit width of the secondinformation according to this second embodiment. On the basis of theoutput SF from the staircase waveform generating circuit 130, theoptical disk master is finally formed with a pit line as shown in FIG.16 such that a width is variable according to the second information. InFIG. 16, a numeral shown in each of pits P1 to P7 relatively shows astepwise level concerning a size of the pit width. More specifically,pits P1 and P2 have the minimum pit width “1”, the pit P3 has a largerpit width “2”, the pit P4 has a further larger pit width “3”, the pit P5has a further larger pit width “4”, and the pits P6 and P7 have themaximum pit width “5”. A range from the terminal end of the pit P2 tothe distal end of the pit P6 is a transition area W where the pit widthof the second information is stepwise changed. The transition area W isrecorded on a compact disk as a second information in a predeterminedrange (e.g., W<1.0 mm), and thus, a record of characters and figures canbe visibly confirmed. If the transition area is too long (e.g., W>1.0mm), the second information recorded on an optical disk is indefinite,and in the case of seeing the surface of the optical disk, it isdifficult to recognize an image information recorded as the secondinformation. Conversely, if the transition area is too short (e.g.,W<0.1 mm), no effect by the transition area is obtained. Therefore, itis preferable that a length of the transition area is set to a range of0.1 mm<W<1 mm. According to the experiment made by the presentapplicant, the best transition area is the case where Wo=0.5 mm. In thissecond embodiment, the output signal SF of the staircase waveformgenerating circuit 130 is set so that the aforesaid transition area ofthe pit width can be obtained.

As described above, the output of the up/down counter 142 outputs astaircase signal SF such that the output value successively varies from0 to 7 according to the change of the second information SE. Thestaircase signal SF is converted into an analog voltage SX controllingthe optical modulator 10A by means of a voltage converter circuit 132having a construction as shown in FIG. 17. A signal SX converted intothe analog voltage becomes a staircase waveform as shown in FIG. 15Dsuch that its value gradually varies in the vicinity of the change ofthe second information.

In the voltage converter circuit 15 having a construction as shown inFIG. 17, the staircase signal SF is connected as an address signal of aread only memory (ROM) 170. The ROM 170 previously calculates andrecords what the laser power should take a value in accordance with thestaircase signal SF having the count values from 0 to 7. To give anexample, the following is a description on the case where the laserpower is changed from 100% to 85% as described in the first half of thissecond embodiment. For example, in the case where a value of thestaircase signal SF is 7, a numerical value 100 is recorded in responseto an address 7 because a 100% laser power is expected. Further, in thecase where a value of the staircase signal SF is 0, a numerical value 85is recorded in response to an address 7 because a 85% laser power isexpected. Further, in the case where the staircase signal SF has thevalues from 1 to 6, a value calculated from a proportional distributionbetween 100 and 85 is recorded.

Of course, the aforesaid example is the case on the assumption that a100% laser power is outputted when the output of the ROM 170 is 100. Infact, taking a conversion gain of a D/A converter 171 and a conversionefficiency of the optical modulator 10A into consideration, there is aneed of determining the value to be recorded in the ROM 170. Moreover,there is the case where there is no linear relationship between thelaser output power and an input voltage to the optical modulator 10A; insuch a case, a properly changed value need to be recorded in the ROM170.

In the manner as described above, the laser output value read from theROM 170 is converted into an analog voltage value SX by means of the D/Aconverter 171, and then, is supplied to the optical modulator 10A, andthus, the output power from the laser 9 is controlled. In a laser beamL2 thus obtained, its output power is gradually and stepwise increasedor decreased according to the staircase signal SF (see FIG. 15D).

The correction value table 71 provided in the edge position correctingcircuit 131 previously records a correction value according to thestaircase signal SF inputted as a higher address.

This correction value table is made in a manner of preparing individualoptical disks for evaluation with respect to all of 8-stage recordinglaser powers, and directly calculating a correction value from theirregenerative signals. Moreover, like another embodiment described later,for example, the optical disk for evaluation is set to have differenttwo recording powers, and then, a correction value table of otherrecording powers may be prepared by using a mathematical operation(calculation) such as interpolation or extrapolation.

In the aforesaid optical information recording apparatus of this secondembodiment, the modulator circuit 4 constitutes a modulation signalgenerating (making) means for generating a modulation signal SB which isvariable in accordance with the first information SA. The staircasesignal generating circuit 130 constitutes a time changing signalgenerating (making) means for generating a time changing signal SF whichis timely variable according to the second information SE. The opticalmodulator 10A constitutes a laser power (light quantity) changing meanswhich changes a laser power according to the time changing signal SF; onthe other hand, the optical modulator 10B constitutes an opticalmodulation means which makes an on-off control of the laser beam L1obtained by the laser power changing means 10A according to themodulation signal SB.

Thus, the optical information recording apparatus of this secondembodiment comprises: a modulation signal generating means forgenerating a modulation signal SB which is variable in accordance withthe first information; a time changing signal generating (making) meansfor generating a time changing signal SF which is timely variableaccording to the second information; a laser power changing means whichchanges a laser power according to the time changing signal; and anoptical modulation means which makes an on-off control of a laser beamobtained by the laser power changing means according to the modulationsignal. The laser beam by the second information is gently changed.Accordingly, in the optical information recording apparatus of thepresent invention, for example, in addition to an information (firstinformation) such as a music and a video determined based on the CD orDVD standards, it is possible to record a second information which isnot determined in the CD or DVD standards in the identical disk.Further, in a optical disk manufactured by the optical informationrecording apparatus of the present invention, a regenerative signalcharacteristic does not suddenly vary in the vicinity of a changingpoint of the second information, and therefore, it is possible to stablyreproduce the information.

Further, in the optical information recording apparatus of this secondembodiment, the modulation signal generating means comprises: a firstmodulation signal generating for generating a first modulation signal bychanging over a signal level at a period of integer multiples of apredetermined basic period in accordance with the first information; achange pattern detecting means for detecting a change pattern of thefirst modulation signal; and a timing correcting means for correcting achange timing of the first modulation signal according to both the timechanging signal and the change pattern so as to generate a secondmodulation signal. Thus, the change timing of the recording signal iscorrected in accordance with a change of laser power and a changepattern of recording signal. Accordingly, an optical disk recordinginformation by the optical information recording apparatus of thepresent invention has a very preferable signal characteristic. Further,it is possible to more largely set a change rate of laser power forrecording the second information; as a result, the second informationcan be more clearly recorded in the optical disk.

Moreover, according to the optical information recording method of thisembodiment, the first information is recorded by mainly turning on andoff controlling the laser beam, and the second information is recordedby mainly changing a light intensity of the laser beam, and thus, thelight intensity of the laser beam is timely gently changed. Further, atiming for turning on and off the laser beam is adjusted according toboth the first information and the light intensity of the laser beam.Accordingly, according to the optical information recording method ofthe present invention, in addition to an information (first information)such as a music and a video determined based on the CD or DVD standards,it is possible to record a second information which is not determined inthe CD or DVD standards in the identical disk. Further, it is possibleto more largely set a change rate of laser power for recording thesecond information; as a result, the second information can be moreclearly recorded in the optical disk.

In an optical information recording medium of this second embodiment,the first information is recorded by mainly changing a pit length andposition, and the second information is recorded by mainly changing apit width. The pit width for recording the second information isstepwise variable. The pit length and position are finely adjusted by asignal patter recorded as a pit and a pit width. Accordingly, in thepresent invention, in addition to an information (first information)such as a music and a video determined based on the CD or DVD standards,it is possible to obtain a medium which records a second informationwhich is not determined in the CD or DVD standards in the identicaldisk. Further, visibly recognizable graphic information such ascharacters and figures is recorded in a disk signal area (section) as asecond information, and thereby, it is possible to provide a value addeddisk. In addition, the graphic information of the optical informationrecording medium of this embodiment is capable of more clearly confirmedas compared with the conventional method.

Description of Third Embodiment

A third embodiment of the present invention will be described below withreference to the accompanying drawings.

FIG. 18 is a block diagram showing a construction of an optical diskapparatus according to the third embodiment. In FIG. 18, like referencenumerals are used to designate the parts corresponding to those shown inFIG. 1, and the details are omitted.

A second modulation circuit 180 inputs the EFM modulation signal SB andthe second information SE, and overlaps the second information SE withthe EFM modulation signal SB so as to hinder a recording information tobe recorded as an EFM signal, and thus, outputs an signal SD.

The second modulation circuit 180 has a construction as shown in FIG.19. In this case, a PLL circuit 190 generates a channel clock CK whichvaries every the minimum change unit of the EFM signal SB, and then,supplies the channel clock CK to a signal overlapping circuit 191 and atiming correcting circuit 192. In the case where the second informationSE is a logic “0”, the signal overlapping circuit 191 outputs the secondinformation SE as a signal SC without adding any modification to theinputted EFM signal SB. Conversely, in the case where the secondinformation SE is a logic “1”, the signal overlapping circuit 191investigates a length of pit formed by a signal patter of the inputtedEFM signal, and then, if a decision is made such that a length of theformed pit is 9T or more, the signal overlapping circuit 191 makes aconversion such that a signal originally recorded as one pit into isreplaced with a signal recorded as two pits and one space, and thus,outputs it as a signal SC.

The signal SC, in which the second information SE is overlapped asdescribed above, is transmitted to the timing correcting circuit 192,and then, the signal change timing is finely adjusted so as to improve aquality of regenerative signal (to reduce a jitter), and thus, thesignal SC is outputted as a signal SD.

As described above, the second information SE is recorded on the diskmaster 2 as a power change of the laser beam L2 by means of the opticalmodulator 10A. Simultaneously, the second modulator circuit 180 convertsa signal according to the second information SE, and then, the opticalmodulator 10B turns on and off the laser beam according to the signal,and thereby, the signal is recorded on the disk master 2. Morespecifically, the signal is modulated double according to the secondinformation, and then, is recorded on the disk master 2; therefore, itis possible to record the second information with a contrast higher thanthe conventional method. Further, the change timing of the recordingsignal is corrected by means of the timing correcting circuit 92;therefore, it is possible to manufacture a preferable disk which hasalmost no a jitter.

FIG. 20 is a view to explain a construction of the signal overlappingcircuit 191 for performing the signal conversion as described above. InFIG. 20, the EFM signal SB is operated by the channel clock CK, and isinputted to 13 latch circuits 200A to 200M which are connected inseries. These 13 latch circuits 200A to 200M sample the EFM signal SB ata timing of the channel clock CK, and then, a change pattern of the EFMsignal SB is detected from the sampling result on continuous 13 points.More specifically, for example, in the case where a latch output“0011111111100” is obtained, it is possible to make a decision that thechange patter is a pattern in which a pit having a length 9T is formed.

AND gates 201 to 203 detect a pit having a length 9T or more from theoutputs of 13 latch circuits 200A to 200M. More specifically, the ANDgate 201 makes a detection that a pit having a length 9T is recorded byoutputting a logic “1” in the case where the output of 13 latch circuits200A to 200M is “0011111111100”. Likewise, the AND gate 202 makes adetection that a pit having a length 10T is recorded by outputting alogic “1” in the case where the output of 13 latch circuits 200A to 200Mis “0111111111100”. Moreover, the AND gate 203 makes a detection that apit having a length 11T is recorded by outputting a logic “1” in thecase where the output of 13 latch circuits 200A to 200M is“0111111111110”.

An output signal MD of an OR gate 204 is obtained by calculating a logicOR of the outputs from the AND gates 201, 202 and 203, and then, the ORgate 204 outputs an signal MD which becomes a logic “1” when any of pitshaving lengths 9T, 10T and 11T is recorded.

In an output of the latch circuit 200F, the EFM signal SB is delayed by7 clocks, and then, appears.

For example, in the case where the pit having a length 9T is recorded,when the latch circuit 200F outputs a 9T pit signal, the signal MDbecomes a logic “1” at the substantially central portion of the 9T pitsignal.

A NAND gate 205 calculates a logical product of the second informationSE from the character signal generating circuit 6 and a pit detectionsignal MD of 9T pit or more from the OR gate 204, and thereafter,inverts a logic, and then, outputs the inverted logic. Morespecifically, in the case where the second information SE from thecharacter signal generating circuit 6 is a logic “0”, the output of theNAND gate 205 always becomes a logic “1”. An AND gate 206 calculates alogical product of the output of the NAND gate 205 and the output of thelatch circuit 200F, and then, outputs it. Therefore, in the case wherethe second information SE from the character signal generating circuit 6is a logic “0”, the output of the latch circuit 200F appears as theoutput of the AND gate 206.

In other words, in the case where the second information SE from thecharacter signal generating circuit 6 is a logic “0”, in the output ofthe AND gate 206, an input EFM signal SB is merely delayed.

On the other hand, in the case where the second information SE from thecharacter signal generating circuit 6 is a logic “1”, the output of theAND gate 206 is forcedly modified into a logic “0” when the 9T or morepit detection signal MD is a logic “1”. Thus, in the case where the 9Tor more pit signal is detected, the output of the AND gate 206 isconverted into a signal such that the central portion of the 9T or morepit signal becomes 0.

A latch circuit 207 latches the output of the AND gate 206 at a channelclock CK unit, and thereby, shapes a waveform, and then, transmits thewaveform as an output signal SC to the timing correcting circuit 192. Asa result, for example, a pulse having a length 9T as shown in FIG. 21Ais modified into two pulses having a length 4T and a blank having alength 1T at the middle portion between these two pulses, as shown inFIG. 21D, and thus, is recorded. Likewise, a pulse having a length 10Tis modified into a pulses having a length 5T, a blank having a length 1Tand a pulse having a length 4T, and thus, is recorded. When a pit isrecorded according to the aforesaid pulse, it is considered that asshown in FIG. 21B and FIG. 21E, a pit is recorded according to eachpulse.

FIG. 21C and FIG. 21F are schematic views showing a expectedregenerative signal. The recording method of this third embodiment isemployed, and thereby, a pit line is recorded as two pits and a blankhaving a length 1T at the middle portion between these two pits. The pitline generates a regenerative signal as shown in FIG. 21F in the case ofbeing read by means of an ordinary pickup. Such a generative signal iscompared with a general threshold level ST, and then, is binary-coded.In this case, it can be seen that a timing crossing the threshold levelST is the same as that shown in FIG. 21C. Thus, according to theaforesaid method, even if a pit having a length of 9T or more is dividedinto two so as to be recorded, it can be seen that there is nogeneration of a jitter. Therefore, it is possible to reproduce aninformation recorded as the EFM signal SB without giving an influencethereto.

In the above manner, the experiment of dividing the pit into two partswas carried out, and thereafter, an actually obtained regenerativesignal was shown in FIG. 22. According to expectation, it can be seenthat there is no influence to a signal in the vicinity of the thresholdlevel.

As is evident from the above description, the pit having a length of 9Tor more is divided into two, and thereby, it is possible to record thesecond information. In comparison with the pit line recorded in thismanner (e.g., comparing FIG. 21B with FIG. 21E), in the case where thepit having a length of 9T or more is divided into two, it can be seenthat the total area of pit is reduced. Thus, the second information isset a value different from other area in a certain area on a disk, andwhen the aforesaid pit is recorded, the area is formed so that the totalarea of the pit is different from other area. In the case where a humanbeing visibly observes such a disk, a light quantity proportional to thetotal area of the pit is observed. Thus, the human being visiblyobserving the disk see as if only specific area on the disk has adifferent color according to the second information. In this manner, itis possible to record patterns such as characters and designs on thedisk without giving an influence to the EFM signal SB.

According to the method described in this third embodiment, an intensityof the recording laser beam L2 is previously modulated according to thesecond information SE. More specifically, as described before, in thecase where the second information is a logic “1”, the intensity of thelaser beam L2 is lowered to a 85% power, and in the case where thesecond information is a logic “0”, the intensity of the laser beam L2 isa 100% power as it is unchanged. In this case, a width of the pitrecorded on the disk is variable according to an intensity of the laserbeam.

Therefore, in the case where the second information is a logic “1”, theintensity of the laser beam is lowered; for this reason, the pit widthbecomes narrow. Further, in the case where the second information is alogic “1” a pit having a length 9T or more is divided into two parts.The aforesaid two effects both serve to reduce the total area of thepit; as a result, the second information recorded on an optical diskaccording to the method of this third embodiment can be more clearlyobserved as compared with the conventional method.

FIG. 23 is a view illustrating a state of pit recorded according to themethod of this third embodiment. In the case where the secondinformation is a logic “0”, the pit is not divided into two parts, andthe recording laser power is 100%; therefore, a pit line as usually (seeFIG. 23A) is recorded. However, in the case where the second informationis a logic “0”, the pit having a length of 9T or more is divided intotwo parts, and further the recording laser output is lowered to a 85%power; therefore, the pit width is relatively reduced. Morespecifically, a pit width (W1) of the FIG. 23A case of becomes widerthan a pit width (W2) of the 23B case. Further, as shown in FIG. 23C, arecording pit having a depression at the middle portion between tworecording pits may be formed without fully diving the recording pit intotwo parts as shown in FIG. 23B, and even if the second information isrecorded on the optical disk in this manner, it is possible tosufficiently visibly recognize an information such as characters andimages. On the contrary, even if the second information is recorded onthe optical disk so that the middle portion between two recording pitsis formed so as to be bulged, likewise, it is possible to sufficientlyvisibly recognize an information such as characters and images. Namely,the middle portion between two recording pits may be formed so as tohave a width relatively different from a recording pit.

When the pit width is varied as described above, there is thepossibility that a jitter is generated in the regenerative signal. Inthe regenerative signal from the optical disk, there exists aninterference between codes from the pattern recorded before and front;for this reason, a jitter is generated. In this third embodiment, inorder to solve the above problem, and to manufacture a high qualitydisk, a signal obtained from the signal overlapping circuit 191 issupplied to the timing correcting circuit 192 so that the signal SDcorrecting a position on a change point of the recording signal can begenerated. In this third embodiment, according to the signal SD thusobtained, the optical modulator 10B turns on and off the laser beam L2,and thereby, it is possible to record both information obtained from thedigital audio tape recorder and the second information SE obtained fromthe character signal generating circuit 6 in the disk surface.

The timing correcting circuit 192 detects a change pattern of the signalSC. Simultaneously, the second information SE is transmitted to thetiming correcting circuit 192. Thus, the timing correcting circuit 192can correct a timing according to both information of the change patternof the recording signal SC and the recording laser power.

Then, in accordance with two information thus obtained the timingcorrecting circuit 192 outputs a modulation signal SD which finelyadjusts an edge position. More specifically, in the timing correctingcircuit 192, a change timing of the output signal SD is finely adjustedin accordance with a recording laser power (85% or 100% power value) anda change pattern of the recording signal SC (a pit length and a apacelength vary), and then, the modulation signal SD is outputted so that ajitter always becomes the best state. In this case, the timingcorrecting circuit 192 has the same construction as the edge positioncorrecting circuit 7 shown in FIG. 6.

More specifically, the modulation signal SD passing through the timingcorrecting circuit 192 is recorded by a predetermined laser powerdetermined according to the second information. As a result, when thedisk thus obtained is reproduced and the regenerative signal isbinary-coded according to a predetermined binary-coded level, a signalcontaining no jitter can be obtained.

Correction is always made with respect to all of the recording laserpower by means of the timing correcting circuit 192; therefore, it ispossible to avoid a problem that a formation of the pit is slightlydifferent for each pattern. As a result, it is possible to manufacture adisk which can make synthetically lower a jitter generated in aregenerative signal. Moreover, in this third embodiment, an edgeposition is adjusted for each recorded pattern; therefore, it ispossible to remove a jitter depending upon the pattern, that is, ajitter generated by an interference between codes.

The modulation signal SC and the second information supplied to thetiming correcting circuit 192 are connected to the rise edge correctingcircuit 60A and the fall edge correcting circuit 60B shown in FIG. 6. Inthe signal SD, the rise edge timing and the fall edge timing arecorrected in accordance with the recording pattern (determined by pitand space length) and the recording power, and thus, the correctedsignal SD is outputted.

According to the output signal SD of the timing correcting circuit 192thus obtained, the laser beam L2 is on/off-controlled by means of theoptical modulator 10B so that the output level is variable between a100% power and a 85% power, and thus, is irradiated to the disk master 2as a laser beam L3.

In the rectangular coordinate position detecting circuit 5, as shown inFIG. 2, the count value RX of the one-rotation count circuit 20 and thecount value TK of the track count circuit 21 are equivalent respectivelyto the angular information and the radius information in the case ofexpressing a position recording at present by the polar coordinate.Thus, the coordinate transforming circuit 22, to which these two valuesare inputted, can calculate and output positional information X and Y onthe rectangular coordinate system. The positional information X and Y onthe rectangular coordinate system are transformed as described above,and thereafter, is transmitted to the character signal generatingcircuit 6.

As described above, in the internal ROM of the character signalgenerating circuit 6, an image to be drawn is binary-coded with the useof the rectangular coordinate system, and thus, is recorded therein. Theinformation recorded in the ROM is inputted so that the coordinatesystem is transformed at a real time by means of the rectangularcoordinate position detecting circuit 5, and therefore, is read out asit is unchanged, and then, is successively recorded on the disk as adata such as a change of recording laser power and a division of a longpit.

In the voltage converter circuit 15 shown in FIG. 17, the secondinformation SE is supplied as an address signal of the read only memory(ROM) 170. The ROM 170 previously calculates what value should be taken,in response to the second information SE having a value of 0 or 1indicative of the recording laser power, and then, records the value. Togive an example, the following is a description on the case where thelaser power is changed from 100% to 85% as described in the first halfof this third embodiment. For example, in the case where a value of thesecond information SE is 0, a numerical value 100 is recorded inresponse to an address 0 because a 100% laser power is expected.Further, in the case where the value of the second information SE is 1,a numerical value 85 is recorded in response to an address 7 because a85% laser power is expected. Further, in the case where the staircasesignal SF has the values from 1 to 6, a value calculated from aproportional distribution between 100 and 85 is recorded.

Of course, the aforesaid example is the case on the assumption that a100% laser power is outputted when the output of the ROM 170 is 100. Infact, taking a conversion gain of a D/A converter 171 and a conversionefficiency of the optical modulator 10A into consideration, there is aneed of determining the value to be recorded in the ROM 170. Moreover,there is the case where there is no linear relationship between thelaser output power and an input voltage to the optical modulator 10A; insuch a case, a properly changed value need to be recorded in the ROM170.

In the manner as described above, the laser output value read from theROM 170 is converted into an analog voltage value SX by means of the D/Aconverter 171, and then, is supplied to the optical modulator 10A, andthus, the output power of the laser beam L2 is controlled.

In the above embodiment, the laser power is variable in two states. Inorder to slowly carry out a change of the laser power, the change oflaser power may be divided into about 8 stages, and then, the laserpower may be successively changed over. Moreover, in order that a propercorrection is always made by means of the timing correcting circuit 192in response to the changing laser power, an information on the laserpower may be inputted as an upper address of the correction value table71 so that the internal correction value data of the timing correctingcircuit 192 is variable in response to a laser power. With the aboveconstruction, the change of laser power is made larger as compared withthe conventional case; as a result, it is possible to record informationsuch as characters and figures, which is capable of being more clearlyand visibly observed, on the disk surface.

The optical information recording apparatus of this third embodimentcomprises: a first modulation signal generating means (modulator circuit4) for generating a first modulation signal SB by changing over a signallevel at a period of integer multiples of a predetermined basic period Tin accordance with the first information SA; a position detecting means(rectangular coordinate position detecting circuit 5) for detecting arelatively positional information on an optical information recordingmedium (disk master 2) of a pickup; a second information generatingmeans (character signal generating circuit 6) for generating a secondinformation SE in accordance with the relatively positional information;a second modulating means (second modulator circuit 180) for modifying apart of the modulation signal SB according to the second information SE;and an optical modulating means (optical modulator 10B) for modulating alaser beam L2 according to an output SD of the second modulating means.Accordingly, in the optical information recording apparatus of thisthird embodiment, it is possible to a visibly recognizable secondinformation SE which is not determined in the CD and DVD standards, in aarea where an information (first information SA) such as a music andvideo determined in the CD and DVD standards.

Moreover, in this third embodiment, the second modulating means (secondmodulator circuit 180) comprises: a signal overlapping means (signaloverlapping circuit 191) for overlapping the modulation signal SB withand the second information SE so as to generate an overlapping signalSC; and a timing correcting means (timing correcting circuit 192) forcorrecting a timing of the overlapping signal SC so as to generate asecond modulation signal SD. The signal overlapping means 191 comprises:a pattern detecting means (latch circuits 200A to 200M, AND gates 201 to203, OR gate 204) for detecting a pattern of the modulation signal SB;and a pulse dividing means (NAND gate 205, AND gate 206, latch circuit207) for dividing a pulse having a predetermined time width (length) ormore into two or more pulses according to an output MD of the patterndetecting means and the second information. Thus, it is possible torecord a second information having a high contrast as compared with theconventional case. Further, it is possible to obtain an optical diskwhich has a more preferable signal characteristic as compared with theconventional case.

The optical information recording method of this third embodimentcomprises the following steps of: generating the first modulation signalSB which is variable at a period of integer multiples of a predeterminedperiod T from the first information SA; detecting a relative position oflaser beam on an optical information recording medium (disk master 2);generating a second information SE according to the relative position;detecting a portion of the first modulation signal SB having no changefor a predetermined time; generating a second modulation signal SD whichis prepared by modifying a portion of the first modulation signal SBhaving no change according to the second information SE; and modulatinga laser beam L2 according to the second modulation signal SD.Accordingly, in the optical information recording method of this thirdembodiment, for example, in addition to an information (firstinformation SA) such as a music and a video determined based on the CDor DVD standards, it is possible to record a visible second informationSE which is not determined in the CD or DVD standards in the identicaldisk area.

Moreover, the modification of the portion having no change is carriedout in the following manner; more specifically, a recording pulse havinga predetermined length or more is divided into two pulses and one space.Thus, it is possible to record a clear second information.

In the optical information recording medium of this third embodiment,the first information SA is recorded by mainly changing a pit length andposition, and the second information is recorded in a manner that, inpits, a pit having a predetermined length or more is divided into twoparts, or is formed so as to have a depressed or bulged portion. Thus,the second information SE forms a two-dimensional pattern on the opticalinformation recording medium (disk master 2). Accordingly, in theoptical information recording method of this third embodiment, forexample, in addition to an information (first information SA) such as amusic and a video determined based on the CD or DVD standards, it ispossible to obtain a medium recording a second information SE which isnot determined in the CD or DVD standards. Further, it is possible torecord a visibly recognizable graphic information such as characters andfigures in a disk signal area as the second information, and thus, toobtain a value added disk. Further, the graphic information of theoptical information recording medium of this third embodiment can bemore clearly confirmed as compared with the conventional case.

Description of Fourth Embodiment

A fourth embodiment of the present invention will be described belowwith reference to the accompanying drawings.

FIG. 24 is a block diagram showing a construction of an optical diskapparatus according to the fourth embodiment. In FIG. 24, like referencenumerals are used to designate the parts corresponding to those shown inFIG. 1, and the details are omitted.

This optical disk apparatus process the EFM signal SB, and then, outputsa control signal S3 to a mastering machine so as to simultaneouslyrecord the EFM signal SB and a second information SE such as a watermark(patter), an image information or the like. The EFM signal SB is aninformation to be stored in a disk, for example, a music, a computerdata or the like. On the other hand, the second information SE is animage information or the like. An output signal is on/off-modulated inorder to transmit an information to be stored in the disk, and then, anamplitude of the output signal is modulated according to the secondinformation SE. A synchronizing signal FG from the spindle motor isinputted to the rectangular coordinate position detecting circuit 5 sothat rectangular coordinates X and Y are generated. The image signalgenerating circuit 6 generates the second information SE on the basis ofthe rectangular coordinates X and Y.

A CPU 247 controls the whole of this optical disk apparatus. The CPU 247measures an input-output characteristic of the optical modulator 10prior to information recording. More specifically, the CPU 247 graduallydisplaces a voltage applied to the optical modulator 10 from a lowvoltage to a high voltage so as to measure an output of the opticalmodulator at the point of that time, and thereby, previously measures aninput-output characteristic as shown in FIG. 28. In the case ofmeasuring the input-output characteristic, a half mirror 11 reflects apart of laser beam to a photo detector in order to transmit a feedbackinformation on a light intensity to the CPU 247.

Further, the CPU 247 makes an access to the correction value table 71 ora power level control table 263 via a memory bus.

The mastering machine is substantially composed of a laser 9, an opticalmodulator 10 and a spindle motor 14. The laser 9 emits a laser beam L1having a light intensity modulated by the optical modulator 10. Amodulated laser beam L2 exposes a disk master 2 which is covered(coated) with a thin film photosensitive sheet. After the exposure, thedisk master 2 is developed in order to make a mold, and thus, a diskstamper is made. Then, an optical disk is manufactured with the use ofthe stamper by injection molding.

In order to form an image on the optical disk thus manufactured, twolight intensities are used. However, a change of the light intensitymust be smoothly and continuously performed. To achieve this purpose,the second information SE is converted into a staircase signal SF by anup/down counter function of the CPU 247.

An information such as an image by the second information SE is recordedby adjusting an edge of an information pit and by modulating a pitwidth. Thus, the EFM signal SB is processed in two steps. In the firststep, a pit edge position is corrected by means of an edge positioncorrecting circuit 243. This circuit 243 stores an input signal in theshift register 70, as shown in FIG. 7. The monostable multi-vibrator 72detects a change edge of signal. Then, the delay circuit 74 and the dataselector 73 shift a detected pulse depending upon a signal pattern afterand before each edge. In this case, a rate to be shifted is stored inthe correction value table 71.

In the second step, in an edge correction signal SC, its amplitude ismodulated by means of a power modulating circuit 244 shown in FIG. 25,and thus, the edge correction signal SC is outputted as an outputmodulation signal S3. The power modulating circuit 244 makes referenceto the power level control table 263 depending upon the staircase signalSF, and thereby, selects a control voltage ENV suitable for an opticalmodulation, and thus, outputs it via a D/A converter 264. Theinformation signal SC and the control voltage ENV are multiplexed bymeans of an analog multiplexor 265, and thereby, an output modulationsignal S3 is generated.

FIG. 26 is a block diagram showing a construction of the CPU 247. Thesecond information instructs a change of light intensity. A photodetector 270 and an analog/digital (A/D) converter 271 are used formeasuring a light intensity of laser beam for measuring the input-outputcharacteristic of the optical modulator 10. A mode selective signal MODEof the control signal instructs a usual cutting operation and achange-over of measurement for characteristic of the optical modulator10. A memory bus signal MOMORY I/O supplies a read and write signal ofCPU 272 for making an access to each memory of the correction valuetable 71 and the power level control table 263.

A timing chart of FIG. 27 shows an operation of power modulation when apower is changed from a certain power level to other power level. Thestaircase signal SF indicative of a recording power level slowlyincreases from 1 to 8 with respect to a change of the second informationSE from a low level to a high level, and also, the control voltage ENVincreases according to the change. On the analogy of this, in the casewhere the second information SE changes from a high level to a lowlevel, the staircase signal SF and the control voltage ENV slowlydecreases. A voltage of each power level is stored in the power levelcontrol table 263.

In this case, it is noticeable to determine a correction table relativeto the correction value table 71 and the power level control table 263.In the correction value table 71, it is estimated that a proper shiftvalue of a specific recording power is determined by an algorithmdisclosed in Unexamined Patent Publication (Kokai) No. 10-31825.Measurement and analysis of a regenerative signal of a sample disk froma disk reproducing apparatus are made on the basis of the algorithmdisclosed in Unexamined Patent Publication (Kokai) No. 10-31825, andthereby, the reproducing apparatus is driven so that a requiredcorrection shaft is carried out. Such processing is applied between ahigh power and a low power used for recording the second information. Ashaft value of an intermediate power level is obtained from a linearinterpolation.

In the sum of an N-kind power level, a pattern of the EFM signal is setas P, and the staircase signal SF takes a value i. On the aboveassumption, a shift value S_(i) interpolated in an intermediate powerlevel is expressed as the following mathematical equation 3.S _(i)(P)=S _(i)(P)+{i/(N−1)}·{S _(N)(P)−S _(i)(P)}  Mathematicalequation 3:

The interpolated shift values S_(i) (P) and S_(N) (P) are respectively ashift value of low power recording and high power recording. As a resultof the above interpolation, the above values are stored in thecorrection value table 71 as the uppermost address. In the power levelcontrol table 263, the same method as described above is employed.However, the optical modulator 10 has a non-linear characteristic; forthis reason, even if the control voltage is simply linear-interpolated,a smooth change is not obtained.

In order to explain the above problem, a characteristic shown in FIG. 28is recited as an example. FIG. 28 shows a measurement example of a laserbeam intensity of an optical acoustic modulator with respect to adriving voltage (Regarding the principle and characteristic of avariable optical modulator, please refer to Goodman. Introduction toFourier Optics. McGrow-Hill, 1996.) In this example, when the drivingvoltage is 0.5 V, an inclination of the laser beam intensity has asudden gradient; however, when the driving voltage is 1 V, the laserbeam characteristic becomes the peak. When the driving voltage is 0.5 V,the same voltage step causes a sudden change of the laser beamintensity; however, when the driving voltage is 1 V, the laser beamintensity is unchanged.

In the case of carrying out a cutting operation, the voltage is variablelike a step, and with the change, an edge correction is also variable.However, if the optical modulator 10 has a non-linear characteristic asshown in FIG. 28, a non-adaptation is generated between the correctionof edge position and a change rate of recording power. Thisnon-adaptation is measured (observed) as an overshoot in the vicinity ofa change-over of the regenerative signal, as shown in a regenerativesignal example in FIG. 30A; as a result, a jitter is worsen.

For this reason, a correction is made on the laser power. Thiscorrection comprises the following two steps. In the first step, anintermediate intensity value P_(i) is determined by a linearinterpolation between end portion powers P₁ and P_(N) as shown in thefollowing equation 4.P _(i) =P ₁ +{i/(N−1)}·(P _(N) −P _(i))  Mathematical equation 4:

Next, with the use of the obtained input-output characteristic of theoptical modulator 10, a driving voltage value is determined from eachP_(i). This driving voltage is obtained from the previously determinedcharacteristic (e.g., FIG. 28) of the optical modulator by carrying outan inverse operation (calculation). More specifically, concerning acertain power value PI, a coordinate on the point of intersection ofcharacteristic curve is determined, and then, a voltage is obtained fromthe coordinate. A voltage V is obtained by carrying out an invertoperation of the input-output characteristic of the optical modulator,and the voltage V is set as a driving voltage V stored in the powerlevel control table 263.

When plotting the corrected edge timing and the driving voltage thusobtained on a graph, a “butterfly” type signal as shown in FIG. 29 isobtained. As seen from FIG. 29, in a power interpolation of this fourthembodiment, a voltage having a non-equal interval is observed on theoutput voltage axis.

FIG. 30B shows an envelop signal of a regenerative signal of a sampledisk recorded with the use of the correcting technology of this fourthembodiment. As is evident from FIG. 30B, the envelop signal is differentfrom that shown in FIG. 30A, and varies so as to be smoothly amplifiedwithout an overshoot.

Thus, this fourth embodiment provides an optical information recordingapparatus which records a first information signal on an opticalinformation recording medium by carrying out an on/off modulation of alaser beam source at a period of integer multiples of a predeterminedbasic period in accordance with a data to be recorded, and which recordsa change from a predetermined light intensity level to other lightintensity level, which is obtained from a micro equal interval step suchthat an inclination of the light intensity becomes substantially linearwith respect to a second information signal and time by changing a lightintensity of the laser beam source, on the optical information recordingmedium, comprising: measuring means for measuring a laser intensity ofthe modulated laser beam; control means for controlling a driving signalof the modulated laser beam; characteristic measuring means formeasuring a characteristic of laser beam intensity with respect to apredetermined pair of amplitudes of the driving signal obtained by themeasuring means and the control means; characteristic inverting meansfor carrying out an invert operation of the characteristic so as todetermine a driving amplitude corresponding to a certain lightintensity, and storing the result; and timing correcting means forcorrecting a timing of the modulated signal in accordance with a lightintensity level of the laser beam, in the characteristic inverting meansstoring a driving amplitude for making a desired light intensity output,the light intensity of the laser beam being directly controlled during achange by investigating a necessary driving amplitude, and further, theresultant regenerative signal of the optical information recordingmedium being smoothly variable in a recording range where a recordinglight intensity changes so that the optical information recording mediumcan be safely reproduce. Therefore, a non-linearity of the opticalmodulator is corrected, and a change-over of a proper pit edge dependingupon an intermediate recording level is selected, and further, adifference in light intensity between two recording levels is madelarger. Whereby it is possible to record a range of smooth changebetween two recording levels, and to realize a desirably smooth changebetween two watermark patterns. Further, a difference between two lightintensities is made large, and thereby, it is possible to record a moreclear “watermark patter” on the optical disk.

Further, this fourth embodiment provides an optical informationrecording method which records a first information signal on an opticalinformation recording medium, and which records a change from apredetermined light intensity level to other light intensity level,which is obtained from a micro equal interval step such that aninclination of the light intensity becomes substantially linear withrespect to a second information signal and time by changing a lightintensity of the laser beam source, on the optical information recordingmedium, and further includes a timing correcting step applied to thefirst information signal in accordance with a light intensity level,comprising the following steps of: a measuring step of measuring a laserintensity of the modulated laser beam; a control step of controlling adriving signal of the modulated laser beam; an invert operation step ofmeasuring a characteristic of laser beam intensity with respect to apredetermined pair of amplitudes of the driving signal obtained by themeasuring means and the control means, and carrying out an invertoperation of the characteristic, and further, storing the invertoperation value which is a driving signal corresponding to a certainlight intensity; and a timing correction value determining step ofdetermining a timing correction value relative to an intermediate lightintensity level in a displacement period of linearly interpolating atiming value at a predetermined light intensity level, in the invertoperation step of storing an invert operation characteristic for makinga desired light intensity output, the light intensity of the laser beambeing directly controlled during a change by investigating a necessarydriving amplitude, and further, the resultant regenerative signal of theoptical information recording medium being smoothly variable in arecording range where a recording light intensity changes so that theoptical information recording medium can be safely reproduce. Therefore,a non-linearity of the optical modulator is corrected, and a change-overof a proper pit edge depending upon an intermediate recording level isselected, and further, a user can select a desirable difference in lightintensity between two recording levels. Whereby it is possible to recorda range of smooth change between two recording levels, and to realize adesirably smooth change between two watermark patterns.

Further, this fourth embodiment provides an optical informationrecording medium which can record an information signal by carrying outan on/off modulation of a laser beam source, a plurality of pits beingformed so that a desired information is recorded, and a secondinformation being recorded by selecting a pit having a pit widthselected from predetermined plural widths, the selection of the pithaving plural pit widths being carried out so that a light intensity oflaser beam has a fixed inclination in a predetermined observing time,and in order to correct a change of a reflection light generated by adifference of pit width in a reproducing time, an edge position of thepit being adjusted in position, and thereby, a watermark patter orvisible image of the second information being included in the opticalinformation recording medium while the information signal beingreproduced. Therefore, a non-linearity of the optical modulator iscorrected, and a change-over of a proper pit edge depending upon anintermediate recording level is selected, and further, a user can selecta desirable difference in light intensity between two recording levels.Whereby it is possible to obtain an optical information recording mediumwhich can record a range of smooth change between two recording levels,and can realize a desirably smooth change between two watermarkpatterns.

[Generation of Correction Value Table]

FIG. 31 is a view to explain a process for generating the correctionvalue table 71 used for an edge timing correction in each optical diskapparatus described in the above first to fourth embodiments. Thefollowing is a description on a correction value table in the firstembodiment; likewise, the correction value table is applicable to otherembodiments.

The correction value table 71 is included in both the rise edgecorrecting circuit 60A and the fall edge correcting circuit 60B. Thesecorrection value tables are correctly and suitably set, and thereby,even in the case where a power (intensity) of laser beam L, a pit lengthand an interval between front and rear pits vary, or in the cease wherethe recording laser power varies according to the second information SEsuch as graphics and characters, it is possible to manufacture a diskwhich is constructed in a manner that a regenerative signal crosses apredetermined slice level at a correct timing synchronous with the clockCK (i.e., generating no jitter).

These correction value tables 71 are set in the rise edge correctingcircuit 60A and the fall edge correcting circuit 60B, and the method forgenerating these tables is the same in the circuits 60A and 60B exceptthat a generating condition is different. Therefore, only rise edgecorrecting circuit 60A will be described below.

In the following process, a disk master 2 for evaluation is preparedwith the use of the optical disk apparatus 1, and then, a correctionvalue table 326 is set on the basis of the reproductive result of acompact disk made from the disk master.

In the case of preparing the disk master for evaluation, the opticaldisk apparatus 1 shown in FIG. 1 is provided with a correction valuetable 326 for evaluation criterion. In the correction value table 326for evaluation criterion, a correction value data DF is set and formedso that a center tap output of the delay circuit 74 is alwaysselectively outputted in the selector 8 shown in FIG. 1. Moreover, animage data for evaluation criterion is stored in the image signalgenerating circuit 6. In this process, according to each of 100% and 85%laser outputs, the optical modulator 10B is driven by the EFM modulationsignal S2, and then, the disk master 2 is exposed under the samecondition as a usual process for manufacturing a compact disk.

In this process, the disk master 2 for evaluation thus exposed isdeveloped, and thereafter, is subjected to electro-forming so as to makea mother disk, and thus, a stamper is made from the mother disk.Further, a compact disk for evaluation is made from the stamper in thesame manner as a process for manufacturing an ordinary compact disk.

Incidentally, according to the second embodiment, in this process, thetiming correcting circuit 131 is set to a state of having no effect. Bydoing so, a signal SC having no effect by the timing correcting circuit131 is transmitted to the optical modulator 10B, and then, the diskmaster 2 is exposed by the laser beam L2 having a 100% laser power inthe same manner as manufacturing an ordinary compact disk.

In FIG. 31, a compact disk player (CD player) 322 plays back(reproduces) a compact disk for evaluation manufactured in the abovemanner according to an instruction from a computer 324. At this time,the CD player 322 is controlled by means of the computer 324 so as tochange over an operation, and then, outputs a regenerative signal RFwhose signal level is variable in accordance with a quantity of a returnlight obtained from the compact disk 321 from a built-in signalprocessing circuit to a digital oscilloscope 323. In the compact disk, apit width varies according to a power of the laser beam L, and whenobserving the regenerative signal RF with the use of the digitaloscilloscope, an amplitude of the regenerative signal varies in aportion corresponding to a pit.

With a change of the pit width, a front edge position and a rear edgeposition are variable, and thereby, a great jitter is generated with achange of amplitude, and also, an asymmetry greatly varies. Further, ina portion such as a user area forming a pit by a laser beam of a lowlevel, a jitter is generated from front and rear pits by an interferencebetween codes.

In this stage, a binary-coded level of the regenerative signal is alwaysnot set to a predetermined level like an ordinary compact disk. Further,a pit formation is fully carried out; for this reason, a jitter isgenerated.

The digital oscilloscope 323 is controlled by the computer so as tochange over an operation, and carries out an analog/digital conversionof the regenerative signal RF at a sampling frequency twenty times asmuch as a channel clock; and thus, outputs a digital signal to thecomputer 324.

The computer 324 controls the operation of the CD player 322 and thedigital oscilloscope 323, and processes a digital signal outputted fromthe digital oscilloscope 323, and thereby, successively calculates(computes) a correction value data DF.

Finally, the computer 324 drives a ROM writer 325, and then,successively stores the calculated correction value data DF in a readonly memory, and thereby, forms a correction value table 326. Accordingto the correction value table 326 thus formed, an optical disk can befinally manufactured.

FIG. 32 is a flowchart showing a procedure for making the correctionvalue data DF in the computer 324. In this procedure, the computer 324proceeds step SP2 from step SP1, and then, sets a jitter detectionresult Δr (p, b) and the number of jitter measured times n (p, b) to avalue 0. In this case, the computer 324 calculates (computes) the jitterdetection result Δr (p, b) on front and rear edges of a jitter detectiontarget every combination of a pit length p and a pit interval b, andthen, counts the number of jitter measured times n (p, b). For thisreason, the computer 324 sets jitter detection result Δr (p, b) and thenumber of jitter measured times n (p, b) to the initial value.

Sequentially, the computer 324 proceeds step SP3, and then, makes acomparison between a digital signal outputted from the digitaloscilloscope 323 and a predetermined slice level VL, and thereby,generates a digital binary-coded signal made by binary-coding theregenerative signal RF. Incidentally, the computer 324 binary-codes adigital signal so that the digital signal becomes a value 1 when beingmore than the slice level, and becomes a value 0 when being less thanthe slice level.

Sequentially, the computer 324 proceeds step SP4, and then, generates aregenerative clock from the binary-coded signal made by the digitalsignal. In this case, the computer 324 simulates an operation of the PLLcircuit according to an operational processing based on the binary-codedsignal, and thereby, generates a regenerative clock.

Further, in the next step SP5, the computer 324 samples the binary-codedsignal at each fall edge timing of the regenerative clock thusgenerated, and thereby, decodes a modulation signal (hereinafter, thedecoded modulation signal is referred to as a decoded signal).

Sequentially, the computer 324 proceeds step SP6, and then, detects atime difference (lag) e between the point of time of a rise edge of thebinary-coded signal and the point of time of the fall of regenerativeclock nearest to the rise edge, and thereby, time-measures a jittergenerated in the edge. Next, in step SP7, the computer 324 detects a pitlength p and a pit interval b of the front and rear pits from thedecoded signal with respect to the edge time-measured in step SP6.

In step SP8, the computer 324 adds the time difference e detected instep SP6 to the jitter detection result Δr (p, b) corresponding to thepit length p and the pit interval b of the front and rear pits, andincrements the corresponding number of jitter measured times n (p, b) bya value 1. Sequentially, the computer 324 proceeds step SP9, and then,makes a decision whether or not time measurement of all rise edges iscompleted. If the decision result of negative “NO” is obtained, thesequence returns to step SP5.

Thus, the computer 324 repeats the procedure of stepsSP5-SP6-SP7-SP8-SP9-SP5, and accumulates the time-measured jitterdetection result for each change pattern generated in the regenerativesignal RF, and then, counts the added numbers. The change pattern isclassified into 6 sampling periods (period of 12T in total) based on abasic period T of the jitter detection target edge so as to correspondto the number of latch circuits 70A to 70M in the rise edge correctingcircuit 60A.

When the jitter time measurement is completed with respect to all edge,the computer 324 proceeds step SP10 if the positive result is obtainedin step SP9, and then, makes average the time-measured jitter detectionresult for each change pattern generated in the regenerative signal RF.More specifically, the jitter detected in step SP6 receives an influenceby a noise; for this reason, the computer 324 makes average the jitterdetection result so as to improve a measurement accuracy of jitter.

When the jitter detection result is made average in the above manner,the computer 324 sequentially proceeds step SP11, and then, generates acorrection value data DF for each change pattern from the detectionresult, and thus, outputs each correction value data DF to a ROM write325. In this case, assuming that a delay time difference between taps inthe delay circuit 74 is set as τ, the correction value data DF iscalculated from the following mathematical equation 5.Hr1(p, b)=Hr0(p, b)−(a/τ)·Δr(P, b)  Mathematical equation 5:

In the above equation 5, Hr1 (p, b) is a tap of the delay circuit 74selected from the correction value data DF, and the value 0 is a centertap of the delay circuit 74. Moreover, Hr0 (p, b) is a tap of the delaycircuit 74 selected from the correction value data DF of the initialvalue, and in this embodiment, Hr0 (p, b) is set to 0. In the aboveequation 5, “a” is a constant. In this embodiment, the constant “a” isset to 1 or less (e.g., 0.7, etc.), and thereby, the correction valuedata can be securely converged even if there is an influence by a noise.

The computer 324 carries out a procedure for generating the aforesaidcorrection value data in accordance with each of the cases where thelaser beam L is a 100% power and a 85% power, on the basis of a signallevel of the regenerative signal RF detected via the digitaloscilloscope 323. Even in the case where the power of the laser beam Lfalls, the computer 324 binary-codes the regenerative signal RFaccording to a general slice level, and then, generates a correctionvalue data DF so that the binary-coded signal is generated at a correcttiming.

In the second embodiment and others, the computer 324 carries out theaforesaid operation for each of 8 areas (regions) into which aninformation recording surface of the compact disk 321 is coaxiallydivided, and thereby, generates a different correction value data foreach area. In this case, each of 8 areas is correspondent to one of8-stage laser output.

The computer 324 stores the correction value data DF thus generated in apredetermined address area of the ROM writer 325, and thereafter,proceeds step SP12, and thus, the procedure ends. Sequentially, thecomputer 324 carries out the same procedure with respect to a differentrecording power. Then, the computer 324 carries out the above procedurewith respect to all powers (8-kind power corresponding to the staircasesignals SF 0 to 7), and thereafter, writing is performed by the ROMwriter 325, and thus, an internal correction value table 326 (shown by areference numeral 71 in FIG. 7) of the rise edge correcting circuit 60Ais completed.

Further, the computer 324 carries out the same procedure with respect tothe fall edge of the digital binary-coded signal, and thus, an internalcorrection value table 326 of the fall edge correcting circuit 60B iscompleted.

With the above construction, in the optical disk apparatus of the firstembodiment shown in FIG. 1, each correction value table of the edgeposition correcting circuits 7A and 7B is set to the initial value, thedisk master 2 for evaluation is prepared under the same condition as thecondition of manufacturing the conventional compact disk 321, and then,a compact disk 321 for evaluation is made from the disk master 2.

In the compact disk 321, the laser beam L is on/off-controlled accordingto the modulation signal S2 having a signal level variable at a periodof integer multiples of a basic period T, and then, the disk master 2 issuccessively exposed, and thereby, an evaluation data is recorded inaccordance with a pit length and a pit interval. A power of the laserbeam L falls on the basis of the image data for evaluation criterion,and thereby, a pit area having a narrow width is locally formed, andwith a change of the pit width, the pit length is also variable.

Thus, in the regenerative signal obtained from the compact disk 321 forevaluation, a jitter is generated by an interference between codes ofadjacent pits in a portion where a pit is formed by a fixed laser power.In a portion where the pit width varies, in addition to the interferencebetween codes of adjacent pits, a great jitter is generated by a changeof the pit width. Further, in the portion where the pit width varies, anamplitude of the regenerative signal greatly varies, and also, anasymmetry suddenly varies.

Therefore, in the regenerative signal obtained from the compact disk321, a timing when a slice level crosses varies in accordance with achange pattern of the modulation signal S2 corresponding to a length andinterval of front and rear pits, an exposure position in a radiusdirection, and a laser beam power in exposure, and a great jitter isgenerated in the regenerative clock generated from the regenerativesignal.

The compact disk 321 is reproduced (played back) by means of the compactdisk player 322, and the regenerative signal RF is converted into adigital signal by means of the digital oscilloscope 323, and thereafter,a binary-coded signal, an EFM modulation signal and a regenerative clockare generated by means of the computer 324. Further, in the compact disk321, pit length and interval of front and rear pits are detected by thebinary-coded signal for each edge of the binary-coded signal, and then,a jitter of each edge of the binary-coded signal is time-measured foreach change pattern.

Moreover, the time measurement result is made average for each changepattern, and then, a jitter generated in each power of the laser beam Lis detected together with a jitter generated by an interference betweencodes. In the compact disk 321, according to the jitter thus detected,the above mathematical equation 5 is calculated on the basis of a delaytime difference τ between taps of the delay circuit 74 for each of 8areas into which the information recording surface is coaxially divided,and then, on the basis of a center tap of the delay circuit 74, a tapposition of the delay circuit 74, which can offset the detected jitter,is detected. A data for specifying the detected tap position is storedin the read only memory as a correction value data, and thereby, thedelay time difference τ between taps of the delay circuit 74 is set as aunit for correcting a jitter, and thus, a correction value table 326 isgenerated.

Therefore, in order that an interference between codes of adjacent pits,the audio data SA is recorded in the compact disk 321 according to a pitlength and a pit interval correcting the front edge position and therear edge position, in accordance with a combination pattern of theadjacent pits. Further, a pit having a narrow width is locally formed inaccordance with the image data, and then, the front edge position andthe rear edge position are corrected so as to offset a change of pitlength generated by the change of pit width.

In this serial procedure, in the compact disk 321 of this embodiment,even if the pit width is varied so as to visibly confirm characters bythe image data and image, the front edge position and the rear edgeposition are corrected so as to offset a change of pit length generatedby the change of pit width, and thereby, the regenerative signal RF isbinary-coded according to a fixed slice level, and thus, it is possibleto generate a binary-coded signal at a correct timing. In other words,it is possible to generate a binary-coded signal so as to effectivelyavoid a jitter generated in the regenerative clock CK accompanying witha change of the power of laser beam L. Further, a jitter position iscorrected so as to reduce an interference between codes, and thereby, itis possible to reduce a jitter generated by the interference betweencodes. Thus, the pit width is varied; nevertheless, it is possible tocorrectly reproduce an audio data.

With the above construction, the positional information on exposureposition by the polar coordinate is converted into the positionalinformation by the rectangular coordinate so as to access the imagedata, and then, in accordance with the image data, the pit width isvaried, and thereby, it is possible to readily and visibly recordcharacters and images by the image data in the information recordingsurface of the compact disk 321 by a simple work of merely storing theimage data of bit map format in the image memory.

In this case, in order to correct a change of pit length with the changeof the pit width, and to reduce an interference between codes byadjacent pits, a timing of irradiating a laser beam is corrected, andthereby, it is possible to securely reproduce the audio data even in thecase where a desired data is recorded with a high density.

The aforesaid embodiment has described the case where characters andimages are visibly recorded by changing the pit width of the pitallotted to the audio data; however, the present invention is notlimited to this embodiment. For example, the image or the like may berecorded in a read-in area by changing the pit width of the pitallotting a TOC data.

Further, the aforesaid embodiment has described the case where thecompact disk 321 is manufactured by directly using the correction valuetable 326 prepared based on the compact disk 321 for evaluation;however, the present invention is not limited to this embodiment. Acompact disk for evaluation is newly manufactured with the use of thecorrection value table 326 prepared based on the compact disk 321 forevaluation, and then, the correction value table may be modified basedon the newly manufactured compact disk for evaluation. In this manner,the correction value table is repeatedly modified, and thereby, it ispossible to securely a jitter.

Further, the aforesaid embodiment has described the case where themodulation signal is sampled into 13, and then, a change patter isdetected; however, the present invention is not limited to thisembodiment. As the necessity arises, the number of sampling may beincreased, and thereby, it is possible to make an application to a longrecording information pattern.

Further, the aforesaid embodiment has described the case where thebinary-coded signal based on a reference clock is time-measured, andthereby, a jitter is measured, and then, the correction value data isgenerated from the measurement result; however, the present invention isnot limited to this embodiment. In the case where an accuracy issufficiently secured in practice, in place of measuring the jitter bytime measurement, the correction value data may be generated bydetecting a signal level of the regenerative signal based on thereference clock. In this case, an error voltage between the detectedsignal level of the regenerative signal and a slice level is calculated,and then, the correction value table is calculated on the basis of theerror voltage and a transient response characteristic of theregenerative signal.

Further, the aforesaid embodiment has described the case where a timingof the modulation signal is corrected according to a correction datamade into a table; however, the present invention is not limited to thisembodiment. In the case where an accuracy is sufficiently secured inpractice, in place of the previously detected correction value data, thecorrection value data is calculated by an operation, and thereby, thetiming of the modulation signal may be corrected.

Further, the aforesaid embodiment has described the case where acoordinate transformation is carried out by an operation of thecoordinate transforming circuit 22 (central processing unit); however,the present invention is not limited to this embodiment. The coordinatetransformation may be carried out by a table of the read only memory(ROM).

Further, the aforesaid embodiment has described the case where the FGsignal is counted so as to generate a positional information by thepolar coordinate; however, the present invention is not limited to thisembodiment. The positional information by the polar coordinate may begenerated by various reference signals synchronous with a rotation ofthe spindle motor, and further, a positional information may be detectedby directly detecting a position.

Further, the aforesaid embodiment has described the case where the diskmaster is rotatably driven under the condition of a constant linearvelocity; however, the present invention is not limited to thisembodiment. The disk master may be rotatably driven under the conditionof a constant angular velocity.

Further, the aforesaid embodiment has described the case where thisembodiment is applied to a compact disk; however, the present inventionis not limited to this. The present invention is widely applicable to anoptical disk apparatus which records various data by a pit. In addition,the present invention is widely applicable to an optical disk apparatuswhich records various data by using an apparatus having a transientresponse characteristic of a regenerative signal.

Moreover, in the optical disk apparatus of the second embodiment, withthe use of the correction value table 326 thus prepared, an optical diskis manufactured by the optical disk apparatus 1. In the optical diskthus manufactured, even in the case where the recording power isstepwise varied according to the second information SE, a pit having anideal length is formed according to a power change, and the optical diskis reproduced by a extremely small jitter over the entire surface of thedisk. Further, in the optical disk apparatus of the third embodiment,with the use of the correction value table 326 thus prepared, an opticaldisk is manufactured by the optical disk apparatus 1. In the opticaldisk thus manufactured, even in the case where the recording power isvaried to two stages according to the second information SE, a pithaving an ideal length is formed according to a power change, and theoptical disk is reproduced by a extremely small jitter over the entiresurface of the disk.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a recording apparatus for acompact disk (CD) and a digital video disk (DVD), and a recording methodthereof and a recording medium. According to the present invention, thepositional information on laser beam irradiation position by the polarcoordinate is converted into a positional information by the rectangularcoordinate so as to access the corresponding image data, and then, inaccordance with the image data, a laser beam power is controlled, andthereby, it is possible to visibly and readily record characters andimages on an information recording surface of a CD or the like.

Further, according to the present invention, it is possible to record aninformation such as a music and a video signal on an optical disk byturning on and off a recording laser according to a method which isdetermined in the standards of CD and DVD. Simultaneously, an output ofthe recording laser is gently varied, and a light emitting pulse of therecording laser is divided into two parts, or is formed into a shape ofdepression or bulge, thereby, it is possible to record a secondinformation such as a watermark pattern or a visible image, which is notdetermined in the standards of CD and DVD and is recognizable by seeinga disk, on the identical disk.

1. An optical information recording apparatus which records a firstinformation signal on an optical information recording medium bycarrying out an on/off modulation of a laser beam source at a period ofinteger multiples of a predetermined basic period in accordance with adata to be recorded, and which records a change from a predeterminedlight intensity level to other light intensity level, which is obtainedfrom a micro equal interval step such that an inclination of the lightintensity becomes substantially linear with respect to a secondinformation signal and time by changing a light intensity of the laserbeam source, on the optical information recording medium, comprising:measuring means for measuring a laser intensity of the modulated laserbeam; control means for controlling a driving signal of the modulatedlaser beam; characteristic measuring means for measuring acharacteristic of laser beam intensity with respect to a predeterminedpair of amplitudes of the driving signal obtained by the measuring meansand the control means; characteristic inverting means for carrying outan invert operation of the characteristic so as to determine a drivingamplitude corresponding to a certain light intensity, and storing theresult; and timing correcting means for correcting a timing of themodulated signal in accordance with a light intensity level of the laserbeam, wherein in the characteristic inverting means storing a drivingamplitude for making a desired light intensity output, the lightintensity of the laser beam is directly controlled during a change byinvestigating a necessary driving amplitude, and the resultantregenerative signal of the optical information recording medium beingsmoothly variable in a recording range where a recording light intensitychanges so that the optical information recording medium can be safelyreproduced.
 2. The optical information recording method which records afirst information signal on an optical information recording medium, andwhich records a change from a predetermined light intensity level toother light intensity level, which is obtained from a micro equalinterval step such that an inclination of the light intensity becomessubstantially linear with respect to a second information signal andtime by changing a light intensity of the laser beam source, on theoptical information recording medium, and further includes a timingcorrecting step applied to the first information signal in accordancewith a light intensity level, comprising the following steps of: ameasuring step of measuring a laser intensity of the modulated laserbeam; a control step of controlling a driving signal of the modulatedlaser beam; an invert operation step of measuring a characteristic oflaser beam intensity with respect to a predetermined pair of amplitudesof the driving signal obtained by the measuring means and the controlmeans, and carrying out an invert operation of the characteristic, andfurther, storing the invert operation value which is a driving signalcorresponding to a certain light intensity; and a timing correctionvalue determining step of determining a timing correction value relativeto an intermediate light intensity level in a displacement period oflinearly interpolating a timing value at a predetermined light intensitylevel, wherein in the invert operation step of storing an invertoperation characteristic for making a desired light intensity output,the light intensity of the laser beam is directly controlled during achange by investigating a necessary driving amplitude, and the resultantregenerative signal of the optical information recording medium issmoothly variable in a recording range where a recording light intensitychanges so that the optical information recording medium can be safelyreproduced.
 3. An optical information recording medium which can recordan information signal by carrying out an on/off modulation of a laserbeam source, a plurality of pits being formed so that a desiredinformation is recorded, and a second information being recorded byselecting a pit having a pit width selected from predetermined pluralwidths, the selection of the pit having plural pit widths being carriedout so that a light intensity of laser beam has a fixed inclination in apredetermined observing time, and in order to correct a change of areflection light generated by a difference of pit width in a reproducingtime, an edge position of the pit being adjusted in position, andthereby, a watermark pattern or visible image of the second informationbeing included in the optical information recording medium while theinformation signal being reproduced.